DE2555014A1 - SEMICONDUCTOR ARRANGEMENTS - Google Patents

Description

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' PHB 32482

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"Semiconductor Devices".

The invention relates to semiconductor arrangements, in particular, but not exclusively, photosensitive arrangements, such as solid imaging arrangements and photodetector arrays.

In many electronic applications an element is required, its electrical conductivity can be controlled by means such as light radiation and with a high response speed can work and provides high gain. For example, for mapping applications, a Photosensitive element required that has a

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high amplification and a fast response speed having. Usual photoconductors, such as cadmium sulfide, have a relatively high gain, but a relatively slow response speed because the reinforcement mechanism is obtained by increasing the life of Load carriers is extended by trapping effects.

Extensive attempts have been made over the past twenty years to use the conventional vacuum tube image intensifier by an aluminum solids equivalent to replace «The main advantages are lower weight, cheaper individual parts, lower ones Operating voltages, more compact structures and the possibility of forming arrangements large surface area in the form of thin panels. The main characteristics of all image intensifiers are their presence a detector, an amplifier and a reproducing device. In current vacuum tubes are these through a photocathode, a secondary emission multiplier or an accelerator with an adjoining fluorescent screen educated. Solid image intensifiers usually contain a secondary photoconductor as an essential component, as a detector and amplifier with a subsequent electroluminescent screen. The solid equivalent of secondary emis-.

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sion multiplication is avalanche amplification and albeit this equivalent to use as an amplifier has been taken into account, sufficiently high gains have not yet been achieved in practice achieved sufficient stability. Although useful image storage arrangements using the photoconductor together with the electroluminescent system have been produced, the response time is particular too long to keep moving objects at low light levels and high gains to observe.

Although so far some semiconductor arrangements in the form of an inhomogeneous body with semiconductor material grains, e.g. a powder layer in a suitable binder, have been produced, the invention is based on a new concept based on the knowledge that if in a inhomogeneous bodies with grains of semiconductor material, the formation of the body takes place in such a way that the type the contacts between the individual grains thereby it is regulated that at least certain substances that change the conductivity type are intentionally given to the body If individual grains are added in the vicinity of the aforementioned contacts, it is possible to create a structure form, in the field effect control of conductivity can be obtained 'what scheme at least

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partly from external influences, like more noticeable Radiation, atmosphere, temperature and incident electrical charge, is independent.

The invention is further based on the knowledge that the application of such Field effect control of the conductivity to a new one Convergence of image detection and amplification, creating a possibility of high amplification, a high degree of detection, a short response time, a variable integration time and a large range of spectral sensitivity is obtained.

The type of amplification that occurs in multiplier devices such as electron multipliers and avalanche diodes is essentially instantaneous. An input current creates a real increase in the number of charge carriers available for conduction across any outside conduit. On the other hand photoconductive gain is obtained when the life duration of a _T or of the two photοerzeugten the input or primary current forming carrier is long enough to allow an effective increase in the available carrier for line occurs. If both carriers are simply picked up by the electrodes, an electron effectively passes through the external circuit and the gain is equal to 1. For

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Reinforcement of more than 1, at least one support must be added to an electrode and the life The duration of one of these carriers must be longer than its duration between the electrodes.

Said lifetime value can be increased by reducing the probability of recombination of photoexcited electron-hole pairs is reduced. Materials with a suitable high lifetime values for electrons have hole traps which, when full, have a small one Have capture cross section for electrons. These traps also set the effective hole mobility thereby reducing recombination at the electrodes.

If no further operations were to be performed, it would be the fall time of the photoconductor after the end of the lighting equal to the specified service life of the carrier. In practice much longer decay times have been found and are attributed to electron traps. If those are deep enough, they can reduce the recombination speed of free electrons rather than that Regulate the hole capture process. They can also have the effect of increasing the effective electron mobility and thus reduce the gain G. As a result, values of gain

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G ί2 £ 10 for cadmium sulfide with decay times of several Seconds noted while much higher gains because of geometry, agility, and tension should have occurred if the decay time corresponded to the life of the carriers.

The present invention is based in part on the initial concept that photoconductive Reinforcement is accepted, but that measures are in place to raise funds to external and continuous regulation of the critical parameter, namely the carrier life, to be provided.

The requirements besides reinforcement of a photoconductor system can be summarized as follows: ■

(a) a high degree of absorption of incident i ": t - '-. η; photons;

(b) a high degree of separation of photoexcited

Electron-hole pairs in a short time t;

(c) "■ a high mobility for one of the photoexcited carriers;

(d) ohmic contacts;

(e) Appropriate removal of the movable beam in a very short time (t) after a given period (t.);

(f) precise external regulation of this integration time (ΐ _± );

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(g) t. must ^ ^ t and t + t. must ^ the in-

\ o / ^ ^ ^ S Γ 1

integration time of the eye (t) for the observation of dynamic images.

Requirements (c) and (e) also require.,. I that deep-in-mass electron traps should be absent.

The expression for the gain is

where t is the transit time between the electrodes. t

The effective response time is the integration time

t. equivalent and can be over the range t / t. / t A r ^ ι ^ * e

can be changed to observe dynamic images. For image storage purposes, t. bigger than t be.

In order to meet these requirements as much as possible, especially with regard to the critical Level (e), structures falling into the following two categories are important, namely:

1) those who are normally in the dark!.-.- ". 5 are non-conductive and where photo-generation leads to a conductive imbalance condition, and

2) those that are normally conductive in the dark and those that are

r j supply in a non-conductive imbalances

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are brought to weight.

Common photoconductors are included in the first category, and it is evident that the Requirement (s) above could be met in that trapped holes by field or photo effects removed. This can of course also be achieved by removing the electron traps alone will.

The second category includes some form of depletion of free charge carriers a stored charge to reach the non-conductive state during the gradual neutralization this stored charge by photo-generated carriers leads to photosensitivity. The requirement (fe) can then be met that the stored charge from an external. ren source is replaced at specified intervals. The invention is further based on the knowledge that in the second category of arrangements charge storage effects that are already present in the single crystal Semiconductor device technology in junction field effect transistor (JFET) structures is known are, can be exploited in a completely different area, in which the semiconductor arrangement semiconductor material grains contains.

For operation in a charge storage mode

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suitable semiconductor devices, e.g. tT-eff plates from Vidikon recording tubes are known. Certain JFET structures can also be used in a Charge storage mode can be operated. In relation to the operation of a JFET structure in a charge storage mode see British Patent No. 1,391,934. One in one Charge Spexchermode operated JFET structure is an ideal imaging element because it is not only has a high response speed, but also a significant gain, while a non-destructive one It is possible to query what is done either during a number of times in a picture period the application of separate interrogation pulses or continuously can be done during an image period by applying a constant interrogation voltage can.

According to the invention, a semiconductor arrangement is characterized in that it is an inhomogeneous Contains body in the semiconductor material grains are present, while the contact between adjacent grains is such that in the interface areas There is continuity between the masses of the adjacent grains, with the main current conduction paths in the body within the grains via the interface areas at the contacts between

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aclien extend to the individual grains and these current conduction paths are not completely exhausted under thermal equilibrium conditions at rest are, and where means for storing charge within the body on the surfaces of the grains, at least locally to the interface areas at the contacts between the individual grains limits, are present, which means the control of electrical conductivity at least part of the body by surface field effect exhaustion of the lines between adjacent ones Grains in the interface areas at the contacts allow between the individual grains in said body part.

In the case of an arrangement according to the invention the conduction of electricity in the body between adjacent grains is not significantly different from the physical Properties of a lock depend on the interface at the contact between individual grains

-Together and at right angles to the direction of current flow extends between said adjacent grains, as in certain known arrangements may be the case with semiconductor powder grains in a binder, but is primarily through electrical Controlled field effect of a lock, which is formed by the means for storing charge

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or interacts with these and is almost in the direction of the current flow between the said adjacent grains extends. It has been shown that by such a configuration a Arrangement with a body with semiconductor material grains that such control of the power conduction in the interface areas at the contacts between If the individual grains become possible, substantial advantages can be obtained with different structures as will be described below.

The term "idle state" is to be understood here as the state in which the external influences, the state of charge at the contacts between the. individual grains, e.g. Illumination in the case of a light-sensitive arrangement or conspicuous gas atoms in a gas detector arrangement, are absent. Under the term "continuity" between the masses of the adjacent Grains is to be understood here as the fact that, apart from the masses of the grains, there is no essential interface layer is present, although in certain cases small concentrations of atomic defects or impurities, e.g. impurity atoms or adsorbed gas atoms, which previously before the formation of the body with the contacts between the individual grains on the surfaces of the

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Grains were present. In general, if the material of the grains before the formation of the said Body, e.g. as a layer on a substrate, is such that on the surface of the grains certain depletion agents initially present, e.g., a depletion surface layer or adsorbed Atoms, Mplekule or ions, are present in the formation of the body so the grains together contacted that this means of exhaustion from the interface areas at the contacts between the individual grains can be removed. The processing method used in each special case will be determined by the particular materials, but the desired contacting can be in certain Cases with a relatively small force exerted between adjacent grains are obtained, as it is generated e.g. by a spinning process. In other cases the desired contact can be made require treatment at high temperature, with even such high temperatures Can be applied that the treatment is a sintering process, or at least the first Sintering steps, approaching. In all cases it is essential Factor the type of contact between individual grains and in general will be the case inventive arrangements of known structural

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doors with semiconductor grains assumed that some combination of the ^ orm of the contacts between the individual grains and the means of Modification of the conduction paths in the body via these contacts is applied. In many known arrangements with semiconductor powder grains in Sch.ich.ten with With a thickness of several grains, the effect depends to a large extent either on an insulating layer between the grains, as in AC electroluminescent devices, or from interposed ones rectifying locks between the grains, as in a lead sulfide photoconductor arrangement, away. In general, in an arrangement according to the invention, the means for storing Charge adjoin the interface area at a contact between individual grains and such Have a shape that there is a sufficient number of chargeable states per surface unit are to the conduction paths in the interfacial areas exhausting at the contacts between individual grains, but an external control the degree of occupation of these states must be possible. This can be known with some more Structures are compared in which such states under thermal equilibrium conditions the arrangement are full at rest and that

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Interface area at a contact between individual grains is completely exhausted. Also differentiate in relation to the processing according to the invention Arrangements in many cases of known structures in that processing any includes a special step to attach the said means for storing cargo, and this step is usually done after the desired continuity of contacts is obtained between individual grains, e.g., after some heating step has taken place.

Some arrangements according to the invention can be adapted to operate in a charge storage mode be and contain electrode means for applying a suitable potentialimpttlses for charging of the body close to some of the contacts between individual grains and for deriving purposes an output signal indicating the electrical conductivity at least a part of the body that is stored in it by the in this way Charge is determined.

Those inside the body at least locally on the surfaces of the grains that adhere to the Interfacial areas adjoin the contacts between individual grains, available means for Storage of charge can be one or more

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have a large number of different shapes. Thus, in a simple embodiment, these means can contain an insulating layer on the said grain surface lies and over the one effective means, such as a gas, can diffuse on the outer surface of an effective means, such as a Gas, can be adsorbed.

Included in another embodiment this means an insulating layer lying on said grain surface, being charge trapping agents are incorporated into the insulating layer, at least in that part of the is in the vicinity of the interface areas at the contacts between the individual grains. at certain embodiments of the arrangement according to the invention form said means for Storage of charge within the body on the surfaces of the grains, at least locally are adjacent to the interface areas at the contacts between individual grains, rectifying locks at or near this grain surface.

In general, the inventive arrangements in which the means for Storage of charge form rectifying locks, divided into at least two main categories.

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The first category includes those arrangements in whose structure there is no separate from sere electrical There is a connection with the means for storing charge which form the rectifying locks, so that it is not possible to directly use the potential applied to the means mentioned to control. The second category includes those arrangements which have some external structure in their structure electrical connection to the means for storing charge which form the rectifying barriers exists, e.g. an ohmic connection with the aforementioned forming the rectifying barriers Agents, if they are in the form of surface layers on the grains, or an indirect one Connection to the means forming the rectifying barriers, e.g. a capacitive connection with such rectifying barrier forming means.

In general, arrangements belonging to the first category can be set up for operation in a charge storage mode, that is to say for operation through which the contacts between individual grains are charged either periodically or intermittently and the electrical conductivity of at least a part of the thus charged body to one of these Charging the following 609826/1001

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The point in time and before the total recombination of the stored charge carriers is determined by some additional effect, e.g. by the introduction of free charge carriers, which are generated by the absorption of radiation in the vicinity of the contacts between individual grains, as in one for imaging or photodetection purposes established arrangement is the case. When such arrangements are operated in a charge storage mode, the manner in which the contacts between individual grains are charged depends on the nature of the means forming the rectifying barriers, as will be described below, but in general the effect is such that the potential difference is temporarily applied between connections with separate parts of the body in order to obtain the desired charging of the contacts between individual grains.

In general, arrangements belonging to the second category for operation in a charge storage mode can be used or a continuous mode and the special structures are then designed for the intended mode of operation. With such arrangements, if They are designed for charge storage mode operation, charging the contacts between

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individual grains are made in a different way than in the arrangements of the first category, because a connection can be used with the rectifying barrier forming means zuiji attaching the charge can. For example, charging can be done by applying a pulse that temporarily rectifying locks biased in the reverse direction when a near ohmic connection with the the latter exists, or if there is a capacitive connection in series with the rectifying locks constituting means consists in that a pulse is applied which temporarily biases the rectifying barriers in the forward direction and charges the capacitor means arranged in series in such a way that when the Impulse the charge between said capacitor means and the rectifying locks near the interface areas at the contacts is distributed between individual grains. In these cases, when the body as a layer is formed, there may be a number of connections, all ohmic or all capacitive are and each establish a connection with the means that the rectifying locks a Form elementary part of the layer. It is evident that the connections with the rectified

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Tending lock-forming means must be such that after charging these connections against each other must be isolated to prevent the leakage of charge from one elementary part of the layer to one to avoid other elementary part of the layer.

Arrangements belonging to said second category can advantageously be used for a continuous Be set up operating mode, wherein the to a connection with the rectifying Lock-forming means applied potential is used to reduce the flow of current by field effect exhaustion the conduction paths between adjacent grains in the interface areas at the contacts to modulate between individual grains.

In one embodiment, a Anoi-dnung said first category in which no external electrical connection with the rectifying barriers forming agents is _f, the distribution of the grains "in the body and the configuration of the rectifying barriers such that after applying a Aufladepotentialunterschiedes of a suitable size over at least a part of the body charge in areas of exhaustion belonging to the rectifying spexes in the vicinity of at least some of the contacts between individual grains in the part mentioned and stored for this purpose.

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is used, the main power lines over the body ner to change in the mentioned part. In one embodiment of the operation of such an arrangement has a query potential difference that is about the said part is applied, the same polarity as the charging potential difference, but a smaller size. In general, charging is carried out in such a way that in the case of an ideal Contact between two spherical grains with a "neck" part in the interface area reduces the charge symmetrically in the interface area between the distributed over the two grains. In the context of the invention, however, are those arrangements in show a certain asymmetry in the charge distribution, e.g. due to selective ion adsorption one side of the contact between two grains by the potential drop across this contact, occurs.

In the one embodiment mentioned the arrangement in which there is no external electrical connection with the rectifying locks constituting means · can control the distribution of the grains and the configuration of the rectifying Lock be such that after applying a charging potential difference of a suitable size those stored in the areas of exhaustion

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Charge is used to almost the mentioned main current conduction paths over the grains in the mentioned Lock part of the body.

Arrangements according to the invention in which the means for storing charge form rectifying barriers at or near the grain surfaces can be implemented in many different ways. In some structures, the rectifying barriers within the grains are formed by transformed surface layers that adjoin the interface regions at the contacts between individual grains, which surface layers have a conductivity type opposite that of the bulk of the grains in which the current conduction paths are located. For example, inadie..korns can consist of η-conductive silicon or η-conductive gallium arsenide and have p-conductive surface zones that are formed outside the interface areas at the contacts between individual grains and are obtained, for example, by heating the p-conductive silicon or gallium arsenide grains in order to produce the desired contacts between individual grains, which heating takes place in an atmosphere of an acceptor dopant for silicon or gallium arsenide. Other examples are grains which initially consist of n-type lead oxide or η-type lead sulfide and which either during or after handling .609826 / 1001

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development to obtain the desired continuity between the masses of adjacent grains at the contacts between individual grains heating in oxygen takes place to attach p-type surface layers to form the grain surfaces.

In other arrangements, the rectifying barriers are formed by a material that is attached to the grain surfaces, the at least locally adjoin the interface areas at the contacts between individual grains. This Applied material can be in the form of a coating layer on the grain surfaces at least locally be present in the vicinity of the interface regions at the contacts between individual grains. Even can this material as a material relative high resistivity, which is the spaces between the grains in the body fills out.

In some arrangements they are present at least locally on the grain surfaces Material and the grains rectifying pn homo junction barriers. So the body can contact grains, e.g. made of silicon, gallium arsenide, lead oxide., lead sulfide, containing one conductivity type, those with the same starting material, but dated

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opposite conductivity type, are coated.

In other embodiments of the structures in which the rectifying locks through a material can be formed which is at least locally present on the grain surfaces that adhere to the Interfacial areas adjoin the contacts between individual grains, form the material and the grains rectifying pn heterojunction barriers. In one example, the body contains grains made of η-conductive zinc oxide which is at least locally coated with a p-conductive material. For the p-conducting coating material when using η-conducting zinc oxide grains, there are different Possibilities, e.g. the use of p-conducting bled iodide, p-conducting copper oxide, p-conducting lead oxide, p-type zinc telluride, as a coating material. When using p-conducting lead iodide as a coating material, E.g. by using non-stoichiometric lead iodide (excess iodine) it is possible for me to useful acceptor effect of these coatings. change. In another example, the body contains grains made of p-type lead iodide, at least locally is coated with η-conductive zinc oxide or η-conductive lead oxide.

In another example, the

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Body grains of η-conductive cadmium sulfide ', the is coated at least locally with a material selected from the group consisting of p-conducting Copper sulfide, p-type zinc telluride, and p-type Lead iodide is formed. According to another example the body contains grains of p-type zinc telluride which are at least locally coated with a material is coated, which is selected from the group consisting of η-type cadmium sulfide, n-type Cadmium sulfide, η-conductive zinc selenide, n-conductive Zinc oxide and η-conductive lead oxide is formed.

In any of the above arrangements, the coatings on the grain surfaces or surface layers of the conductivity type opposite to that of the grain surfaces may contain a suitable one There should be filler material in the spaces between the grains. With certain below Examples to be described, a conductive filler material is used to bond with the to establish the means forming the rectifying locks.

The following are examples of arrangements in which rectifying locks be formed by a semiconductor material of high specific resistance, the conductivity of which

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Kelttyp opposite to that of the contacting grains and that almost fills the spaces between the grains, the main current conduction paths being in the bodies of said arrangements within the grains and via the interface regions to the Extending contacts between individual grains. In one example, the body contains contacted η-conductive zinc oxide or η-conductive cadmium sulfide grains, wherein in the spaces between the grains p-type zinc telluride of high resistivity is available. In another example, the body contains contacted p-type zinc telluride grains, being in the spaces between the grains η-conductive cadmium sulfide high specific Resistance or η-conductive zinc selenide of high specific resistance is present. Also can the spaces between the grains with an organic semiconductor material of high resistivity, e.g. a dye, the conductivity type of which corresponds to that of the material being contacted Grain is opposite.

When using filling materials with high resistivity in the spaces between It is important for the grains that the specific resistance is chosen so that it is sufficient is high so that (a) the main power lines are

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extend in the body via the contacts between individual grains and (b) in an arrangement for operation in a charge storage mode, after charging, a redistribution of in the interface regions in, near the contacts between individual grains of stored charge over adjacent areas does not occur to a significant extent.

In still further embodiments of the arrangement According to the invention, the material present at least locally on the grain surfaces is a semiconductor material of the same conductivity type as the material of the grains, but of different composition. In one example, the body contains grains of η-conductive zinc oxide, which is a rectifying Heterojunction with a coating of n-conducting Forms cadmium sulfide or η-conductive zinc selenide. In another example, the body contains grains of p-type zinc telluride, the one rectifying Straight transition with an over £ 7 from bankruptcy Forms copper oxide. In general, the relationship between the material of the grains and that of the coating must be such that, for n-type grains, the coating has a higher work function than the material of the grains and for p-type grains the coating has a lower work function than comprises the material of the grains.

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In other embodiments of the arrangement in which the rectifying locks by a Material are formed at least locally on the grain surfaces that adjoin the interface regions is attached to the contacts between individual grains, the body contains grains, which are coated at least locally with an organic dye with semiconductor properties.

In other embodiments of the invention Arrangement, contain the means for storing charge at least on the surface parts of the grains that adhere to the interface areas adjoin the contacts between individual grains, at least one adsorbed gas species, selected from the group formed by atoms, ions and molecules. So in these Arrangements Charge transfer from the grains to the adsorbed gas atom, ion or molecule take place it is necessary that when using η-conductive grains the electrochemical ^ potential the adsorbed species is larger than that of the grains, and that when using p-type grains the electrochemical potential of the adsorbed species is lower than that of the grains. One such charge transfer causes field effect depletion of the grain surface parts nearby

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* HJ-

of the interface areas at the contacts between individual grains and thus serves to establish the main current conduction paths in the body via the interface areas to control the contacts between individual grains. The said charge transfer can be done in certain arrangements that a charging potential difference across a contact is applied between two grains. The charging mechanism can be such that upon formation the arrangement of ions, e.g. oxygen ions, on the Surface parts of the grains in the vicinity of the interface areas are adsorbed on the contacts between individual grains. When creating a suitable The ion adsorption occurs when the charge potential difference over at least one part of the body occurs enlarged by the fact that part of the effective rectifying barrier .an the surface parts biased near the contacts between individual grains in the forward direction. This is the ion equivalent of the charging mechanism, the occurs when a pn junction is made to the said Surface parts is present. When using conductive grains, e.g. η-conductive zinc oxide grains, on which oxygen ions can be adsorbed, the charging mechanism is thus that a neutral oxygen ion from around the

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Contact between two grains and an electron can be supplied from inside the grain. The charging thus leads to 'field effect exhaustion of the main power lines via the interface areas at the contacts between individual grains. This Effect can be used in many applications, e.g. in arrangement structures that are used for a Operation are set up in which the photodesorption of said species is under the control of incident Radiation can take place. Other possible applications where the stress induced of an arrangement structure according to the invention caused adsorption effect can be used are those in which desorption can also be stress-induced. An arrangement structure, in which a stress-induced adsorption effect occurs, can be used for gas detection, gas transport or even set up for use as a voltage controlled catalytic device be.

In a further development of an arrangement according to the invention, in which the storage means Form rectifying barriers of charge on the grain surfaces and thereby obtain the aforementioned barriers there will be a coating on the grain surfaces in addition to that present on those surfaces

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coating is applied, the means for storing charge contain further adsorbed gas ions, molecules or atoms on the surface of the applied coating. The attached coating can consist of each of the above-mentioned materials forming a pn heterojunction and in one In a specific example, the grains consist of zinc oxide and are at least at the interface areas surfaces bordering the contacts between individual grains with a coating of p-conductive Lead iodide provided on its surface Oxygen ions are adsorbed.

In a further embodiment of an arrangement according to the invention, in which the means for Storage of charge forms rectifying barriers on the grain surfaces and these barriers thereby that a coating is obtained on the grain surfaces in addition to that on these surfaces is attached to the existing coating, the means for storing charge continue to contain gas ions, molecules or atoms present in the bulk of the coating material. The applied coating can consist of any of the above-mentioned materials which form a pn heterojunction. the The effect of such an arrangement can be due to stress-induced diffusion of the gas species into the coating

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material, whereby in certain cases the dif-founded species serves to increase the conductivity of the To change the coating material.

In general, the inhomogeneous body of an arrangement according to the invention can be several different have different internal configurations; e.g. he can as a system of almost spherical grains connected to one another by narrow necks, a system rod-like grains connected to one another or a system of geometrically closely adjacent ones Grains with restricted areas with good electrical contact may be present. The external configuration of the body may be, for example, a layer several grains thick, but may in general have any suitable shape for the intended application of the assembly.

The body can be a material that acts as a filler material in the spaces between the grains contained, which is either separated from the means for storing charge or a part this means forms. Such a filler material can give mechanical strength to the body as well the grain surfaces from undesired external active Protect species. Examples of filling materials without an active effect on the contacts between individual grains, e.g. an arrangement

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with a zinc oxide powder layer are dental wax, Polyethylene wax and silicone oil.

Instead of filling the spaces between the grains, the body can use a binding agent contain. The binders can consist of the same material as the filler material, but differ from these filling materials in that they do not completely fill the spaces between the grains to complete. This can be completely closed pores, or through constrictions or even open channels with a width of several grain diameters with each other result in connected pores. This ensures that the inside of the layer is open to gases or even liquids becomes accessible and that the mechanical strength is increased considerably will.

Some embodiments of the invention are shown in the drawings and are described in FIG described in more detail below. Show it:

Fig. 1 schematise ^ a part of an electronic Solid arrangement according to the invention,

Fig. 2 schematically a part of another electronic solid state arrangement according to the invention,

FIGS. 3 (a) and 3 (b) show the voltage waveforms generated during operation of an arrangement according to the invention 609826 / 100-1

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occur in charge spexchermode,

Figures h and 5 schematically in cross section parts of further electronic solid-state arrangements according to the invention,

6 is a schematic cross-section of various other configurations for use in FIG Structure of an arrangement according to the invention, and

Figures 7 and 8 show a part in cross section of two different image intensification arrangements according to the invention,

In Fig. 1, the electronic contains solid arrangement according to the invention a body with a number of η-conductive semiconductor grains 1 on one Glass substrate (not shown), which grains form almost ohmic contacts with one another. In This body extends the main power lines about the grains and the interface areas at the almost ohmic contacts between individual Grains, Di3 contacts between individual grains are such that there is a continuity of the n-type grain material and not a rectifying one Block in a direction transverse to the direction of current flow between adjacent grains in the Interface areas is present. In the schematic representation of FIG. 1, there are five in the body existing center punch 1 together with four contacts 2

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shown between individual grains. In the vicinity of the interface areas at the Koxitakten 2 between individual grains there are means for forming rectifying barriers and in the present example these are shown as p-type layers 3 which extend over the surfaces of the grains, with the exception of the interfaces at the contacts between individual grains Grains. Ohmic electrode connections h and 5 », which in the illustration are present on the two outer grains 1, and in practice a system of comb-like interlocking electrodes can be attached to the body in such a way that they are in ohmic contact with the η-conducting grains .

FIG. 2 schematically shows an idealized shape of a single contact between two grains of the shape shown in FIG. 1 and, by specifying a finite width for the conduction path between adjacent grains at the interface region at the contact between two grains, represents it that with an arrangement according to the invention, when this is in the state of rest under thermal equilibrium conditions, the main flow conduction paths at the contacts between individual grains are not completely exhausted. In a practical example of a shift, this shows exhaustion 609826/1001

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The degree of contact between the individual grains is a statistical spread as a result of the distribution the granular zinc, the neck circumference, the coating thickness and the coating doping level. The conduction path lies in a so-called "throat" in the interface area and it is evident that in the schematic illustration of FIG. 2 the thickness of this Halses is shown exaggeratedly large in relation to the thickness of the p-type layers 3,

Operation of an arrangement of the form shown in Figures 1 and 2 in a charge storage mode will now be described. It is assumed here that the contacts between individual grains initially have a state of thermal equilibrium and the main current conduction paths in the layer in the grains 1 extend over the interface regions at the contacts 2 between individual grains. Excess charge is then introduced into the layer by applying a reset potential pulse "between ohmic electrode terminals h and 5. In this generalized embodiment, the conduction path across the p-type layers has a much higher resistivity than the main current conduction path over the grains 1 on.

Assume that the polarity of the

609826/1001

PHB 32 ^ 82 2.12.75

25550U

applied reset pulse is such that the connection k is positive and the connection h is positive and the connection 5 is negative. At the contacts between individual grains shown in Fig. 1, the presence of the p-conductive layers 3 of high specific resistance changes the electric field distribution, because as a result of the potential drop across the conductive channels in the necks of the interface areas at the contacts between individual grains (see Fig. 2, in which the channel with finite width is shown) the pn junction parts between the grains 1 and the p-conductive layers 3 on the left side of the contacts 2 between individual grains are biased in the reverse direction and the pn junction parts on the right side of the contacts 2 between individual grains are biased in the forward direction. At the pn junction parts that are biased in the forward direction, negative charge is transferred to the p-conductive layer 3 and. on the pn junction parts prestressed in the blocking direction, the associated exhaustion areas extend into the grains. In Fig. 2, the extent to which the areas of exhaustion in adjacent grains extend at a contact between two grains in an equilibrium charge state prior to the application of a reset pulse is indicated by dashed lines 609826/1001

PHB 32482 2. 1 2.75

th lines 6 indicated, while the extent to which the areas of exhaustion extend when the reset pulse V is applied is indicated with uninterrupted dotted lines 7. After you have applied the reset pulse, the excess charge stored in the depletion areas belonging to the pn junctions is redistributed and the depletion areas containing this redistributed charge extend into the grains distributed almost symmetrically around the contacts, these depletion areas being indicated by the chain-like lines 8 in Fig 2 are given. The size of the restoring potential pulse V _n is used to determine the extent to which the depletion areas 8 extend in the conductive channel in the neck in the interface area between adjacent grains, and in the present example these depletion areas are shown in such a way that they extend from opposite sides of the is nearly blocked forth almost meet contact between two grains so that dex ⁿ conduction path between the two adjacent grains in the throat over the channel in the interface region at the contact between the two grains. For certain applications it is desirable to completely exhaust the conduction channels at the contacts between individual grains, even in such a way that the conduction channels 609626/1001

PHB 32482 2.

Be over-exhausted, so the operation afterwards outside of the so-called "pinch-off" state he follows. The reset pulse is selected accordingly for these applications.

It is evident that, although not shown in Fig. 2, the depletion areas are on either side of the rectifying Transition between the η-type grains 1 and the p-type layer 3, i.e. that In all three cases shown, the depletion areas are also in the p-type layer extend. For an arrangement in which the p-type layer is an almost uninterrupted coating or an almost uninterrupted surface layer is ideally the configuration of the grains with respect to the contacts between individual grains and the properties of the p-type coating or the p-type layer chosen in such a way that when a charging pulse results in complete exhaustion causes the neck parts in the interface areas at the contacts between individual grains, the p-type coating or layer also becomes completely exhausted. This is of particular interest when making the assembly in this way is that not only good ohmic electrode connections with the n-conductive material of the grains

-609828/1001

PHB 32482 2.12.J75

are formed, but also when attaching the pleitPtiden Coating or the p-type surface layer through a connection with this material the same electrode means is produced. Thus, the acceptor concentration, the thickness and the Diffusion voltage associated with the junction or the surface layer is chosen accordingly.

After redistribution of the charge can be found in the grains near the contacts between The charge stored in individual grains, for example, can be reduced by free charge carriers caused by Absorption of incident radiation in the exhaustion regions 8 or within a minority charge carrier diffusion length the same are generated. This reduction in stored charge causes the areas of exhaustion 8 to contract, whereby the conductive channels 6 in the necks in the 'interface areas at the contacts between individual Grains · are opened further.

Electrical signals indicating the electrical conductivity of the body between the electrodes k and 5, which is determined by the charge stored in the grains at the contacts 2 between individual grains in the intermediate part of the body, can be obtained by being continuously

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25550H

or intermittently a query potential divided V is applied between contacts 4 and 5, the magnitude of V being much less than the reset pulse V is.

The arrangement can have a suitable structure, whereby the interrogation by non-destructive readout can take place either continuously or many times after the application of the reset potential pulse Y , in that a continuous

H.

lent DC bias voltage V _{T is applied} between the electrode connections k and 5 or that a series of pulses with a size V _{T is applied} between these electrode connections.

When such an arrangement is operated as an optical detector in the normal charge storage mode, a series of reset _{potential pulses V R are} superimposed on a constant DC bias voltage V, as is shown schematically in FIG. The output voltage V _n is measured across the resistor R.

Figures 3 (a) and 3 (b) show the input voltage waveform and the output voltage waveform, respectively, associated with a particular such operating mode. In this preferred mode of operation, the size and the duration of Y- are chosen such that those in the grains at the contacts between individual

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PHB 32 ** 82 2.12.75

Exhaustion regions 8 formed by grains have the effect that the aforementioned StromleituriHjsweg between the electrodes at terminals h and 5 via the contacts between individual grains is blocked _{for an interrogation potential with a magnitude less than V n.} Integrated after applying the reset charging potential V _n

XV.

the body the free charge carriers that are generated by incident radiation, and the output voltage V_, which is _{measured while the * constant interrogation DC voltage V T} is being applied, is a measure of the free charge carriers that are generated by the absorption of radiation in the areas of exhaustion and within a Minority carrier diffusion length of the same are generated in the period after the application of the reset pulse V_. Fig. 3 (b) shows the output voltage V during frame periods t ", t-,,

OF ₁ F ₂

t, t etc. During the picture period t ™ is the intensity of the incident radiation is high; no radiation falls during the image period t “

^F 2
a; radiation falls during the image period t

^F 3 on, but with one that is in the image period t "

intensity falling below, and during the image period t_, radiation occurs whose intensity

^F 4

sity which corresponds to the image period t "■. the

Output voltage Y decreases during t ^ as a result of the

OF ₁

Saturation effects of the body and becomes saturated,

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when the bodies have completely discharged, after which at the end of t ^ when the reset position is applied

^F 1

charging potential V drops to zero, whereby the line

Sx

path between the electrode connections h and is blocked. Since during t no radiation

^F 2
falls, the output voltage V remains zero

and decreases during t when incident radiation

^F 3

again, the body again integrating the free charge carriers that were generated during t_

^F 3 will be. The value of the output voltage V depends on the value of the load resistor R and the total charge passing through the load resistor R during one image period is much greater than the charge removed from the grains by the incident radiation during this period. When R is small, the charge gain can exceed 10.

The arrangement according to FIGS. 1 and 2 can be viewed as a series of JFET structures, an external connection formed by the electrode connection 5 being present at one end of the series and an external drain connection formed by the electrode connection h being present at the other end of the series, and the source and drain regions of a single transistor structure by two adjacent grains at the contact between the two bodies

60982671001

PHB 32482 2. 12 -75

nern are formed and the gate region of such single transistor structure through the p-type Areas is formed on the grains at said contact 2 between the two grains while the gate rectifier junctions through the junctions between the p-conducting regions 3 and the n-conducting regions 1 grains are formed. The channel areas of the individual JFET structures are at the contacts exist between individual grains and are in the preferred mode of operation indicated above blocked periodically. In the arrangement according to FIGS. 1 and 2, the gates of the individual JFET structures can be considered electrically floating because in each of these structures there is an extremely high one Series resistance between the gate and each of the source and. There are drain areas. For the proclamation Exercise the operation of a number of JFET structures as an imaging device in a charge storage mode see British Patent No. I.39I.934i.

The arrangement structure according to FIG. 1 can expediently be used in an imaging arrangement by forming the body as a thin layer with a thickness of several grains and ge Appropriate ohmic connections can be made on the grains at different parts of the layer.

609826/1001

. PHB '32482

2.12_75

The spaces between the grains can be filled with a filling material that is replaced by a conductive or non-conductive material is formed. If such a material is electrically conductive, It is important that this material does not electrically connect the ohmic electrode connections to the grains any imaging element formed in the layer connects in such a way that a path is lower Resistance than that of the way across the Köi'ner will.

It will be appreciated that in a "two clamp" type arrangement, that shown in FIGS. "1 and FIG. 2 in which each gate of the number of JFET structures is electrically floating during two ohmic electrode connections for each imaging element. the η-conductive material of the-grains are present, the p-type layer or the p-type coating 3> which should be effective during operation does not need to be uninterrupted, but rather locally in the vicinity of the boundary areas may be present at the contacts 2 between individual grains. So is the case with a modification the manufacture of the arrangement is controlled in such a way that the p-type coating or the p-type Surface layer is formed locally in these areas.

609826/1001

PHB 3 2.12.75

In another embodiment, the p-type coating or the p-type surface layer, which or which forms the means for generating the rectifying barriers, by a p-type Replaced filling material with high resistivity in the spaces between the grains. Also at In such an arrangement it can be important that this filler material is used for the ohmic electrode connections does not electrically connect to the grains of any elementary part in such a way that a path whose resistance is lower than that of the path over the grains.

In other embodiments, the arrangement structure shown in FIGS. 1 and 2 and described with reference to these figures is modified in a suitable manner and designed as a "three-terminal arrangement" in that a connection is formed with the means for forming rectifying barriers. This connection can be a direct ohmic connection, for example with a p-conductive surface coating or a p-conductive surface layer, such as layers 3 in FIGS. 1 and 2, or with a p-conductive filler material which forms the rectifying barriers with η-conductive grains . The connection can also be a capacitive connection with the means for forming the rectifier 609826/1001

PHB 32482

tend to be barriers, for example in the arrangement according to Figures 1 and 2 with the help of a connection with a conductive filler material with interposition of an insulating layer on the p-conductive layers 3 is obtained on the grains.

In a charge storage operating mode of these arrangements, with a connection being established to the means for forming the rectifying barriers, the contacts between individual grains can be charged via said connection. In the case of a direct connection, the potential applied to this connection is such that the rectifying barriers are temporarily biased in the reverse direction. The connections are isolated after the charging potential has been applied. In the case of a capacitive connection, the applied potential is such that the rectifying barriers are forward biased to charge the series capacitor means. After this charging, the charge is redistributed between said capacitor means and the rectifying barriers. These arrangements can be designed as multi-element arrangements in a common layer, for example in an imaging arrangement, provided that there is suitable insulation between the means for forming the rectifying 609826/1001

PHB 32482-2.12J75

25550U

Locking the elementary parts after charging can be held legally. These arrangements can also be set up for a continuous mode of operation, the connection with the Means for forming the rectifying barrier applied potential is used to control the flow of current via the interface areas at the contacts to modulate between individual grains by field effect exhaustion of the grain material in these areas.

Fig. 4 shows in cross section part of an embodiment in which a capacitive connection with the means for forming the rectifying locks. This arrangement includes a glass substrate 11 on which is deposited an electrode pattern composed of a source part 12 and a drain part 13 consists. There is a layer on top of the glass plate and the electrode pattern from η-conductive semiconductor grains 14 with a Thickness of several grains. The grains have been heated together to create intimate ohmic contacts 16 between to form the individual grains. On part of the surface of the formed by grains Layer is an insulating layer 17 »on which a metal gate electrode layer 18 is located. In the spaces between the grains directly un-

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below the gate electrode 18 is a p-type semiconductor filler material 15 of high specificity ¥ resistance and in the spaces between the grains outside of this part there is an isolate of the filler material 19 · This arrangement can be operated in a charge storage mode in that periodically a reset charge potential to the gate Electrode G and an interrogation voltage between electrodes 12 and 13 is applied. The one shown An arrangement may be a single element arrangement or an element of an imaging arrangement in a layer in which the filler material is alternately made of the p-type semiconductor filler material 15 (under the gate electrodes) and made of the insulating filler material 19. At a As a modification, the gate electrode (s) 18 is or will be in contact directly on the layer surface attached with the p-type filler material.

5 shows a further development of an arrangement for operation in a charge storage mode, wherein a charging potential is applied to a gate terminal on the means for forming the rectifying Lock is applied. This arrangement includes a glass plate 21 on which an electrode pattern is attached, which consists of a source part 22 and a drain part 23. On the elec-

6098 26/100 1

PHB '32482 2.12.-75

electrode pattern and on the surface of the glass plate is a layer of n-type semiconductor grains 24 with a thickness of several grains, the grains have been heated together to form intimate ohmic contacts 2.6 between the individual grains. The surfaces of the grains outside the interface regions at the contacts between individual grains contain p-type coatings which are formed during and / or after this heating stage. In the spaces between the grains in a central part there is a conductive filler material 27 for connecting the p-type coatings together. Outside this central part, the spaces between the grains contain an insulating filler material 28. On the surface of the layer above, and the central part, there is an insulating layer 29 on which a metal gate electrode 30 is located. The operation and application of this arrangement structure are almost the same as those of the previous embodiment (Fig. K).

Fig. 6 shows a sketch of various possibilities for arrangement structures in which the means for storing charge comprises a surface coating or a surface layer of the of the opposite conductivity type, the rectifying block (s) on the grain top

609826/1001

- ■ PHB 32482

surfaces while a connection is made with the means for forming the rectifying barriers. In all of these figures, conductive filler materials are shown hatched. Thus, in Fig. 6 (a), a conductive filler material is used to establish the electrical connection between a gate terminal G and the p-type surface layer on the grains. In Fig. 6 (b), an insulating layer is provided on the surface of the p-type surface layer. In Fig. 6 (c), the p-type surface layer is located in the immediate vicinity of the contact between two grains. In Fig. 6 (d), an insulating layer lies on the localized p-type surface layer and on the remaining surfaces of the beads. In Fig. 6 (e) the structure is the same as that of Fig. 6 (c), with the difference that the gate terminal is made with a metal layer which is separated from the conductive filler material by an insulating layer. In FIGS. 6 (f) and 6 (g), the means for forming the rectifying barriers consist of a p-type semiconductor filler material and otherwise only differ from one another with regard to the gate connections. These output structures can be in various arrangements for operation in a charge storage mode, either through 609826/1001

PHB 32 ^ 82 2.12.75

a single element or arrays formed by multiple elements, and iii arrays for Operation can be used in a continuous mode.

As mentioned above, the means for storing charge by an adsorbed gas atom, ion or molecule are formed. Thus, in an embodiment that is a modification of the Structure according to Figures 1 and 2, the p-type layer 3 is replaced by adsorbed oxygen ions, The effect of this arrangement structure is based on stress-induced adsorption of oxygen ions. It can be set up to operate in a charge storage or continuous mode, wherewith In both cases incident radiation causes desorption of oxygen ions. How also As mentioned above, the means for storing charge may be adjacent to a surface layer or a Surface coating on 'the grains from the opposite Conductivity type an adsorbed gas species on the surface of the surface layer or the surface coating of the opposite conductivity type. So can the layer structure of the arrangement according to Figures 1 and 2 in a suitable manner such that a p-conductive coating is obtained on the grain surfaces, on whose

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Surface adsorbed oxygen ions are present, In a further development, the p-type coating contains an adsorbed gas species and the effect of such an arrangement can occur on the grain surfaces are based on stress-induced diffusion of the gas species into the p-type coating.

A description of some further considerations relating to intergranular JFET implementations now follows. Although the embodiments described so far in the field of application of the solid figure, the intergranular JFET structure can be used in a wide range of semiconductor devices with powder layers with a thickness of several grains used as the starting material will. One powder material that has been specifically selected for study is zinc oxide. The contacts between the η-conductive zinc oxide grains in a layer are assumed to be essentially Ohmic contacts, unless these grains have been coated before making contact. This means that the thickness of any existing interface layer is assumed to be sufficiently small is so that tunneling is very likely and such a layer does not lead to exhaustion effects Cause.

If the surfaces of the η-conductive bodies

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PHB 32482 2.12.75

ner after contacting the one shown in FIG Be coated with a material whose work function is higher than that of the grains a depletion area under the grain surface educated. As mentioned earlier, it is expected that the geometry of the contact, coating and vary the area of exhaustion from one contact to another. Any contact between two grains can consist of many partial contacts with different properties and extreme cases, how much small grains joining two larger grains together must be considered. the The structure of Fig. 2 is intended to represent the general case in which the area of the two grains coexist connecting unexhausted channel by the presence of the coating and its resulting Exhaustion zone is reduced. The effective length of the contact area then depends essentially on the local geometry and effects such as grain growth and neck growth during heat treatment at one corresponding to the initial stages of sintering "Temperature ab. Figure 2 shows a typical situation in a p-coated n-grain neck which could be formed at such a temperature.

If the shown in Fig. 2 as layer 3

609826/1001

PHB 2.12.75

th gate layer forms a homojunction and this layer has an acceptor concentration N and

where the grain donor concentrate is N is the total thickness the transition zone consisting of the two areas of exhaustion

² ^ "(V, + Vj (N + N.)

d =

e N N, a d

where V, = the work function difference between

the n and p zones,

V is the external potential applied to the gate,

C. = The dielectric constant of the free ο

Room (8.85. 10 ¹² p / m),

C- = the electrical constant of the n and p zones.

A complex expression is necessary for a gate layer forming a heterojunction, but for the sake of simplicity it is assumed that the acceptor concentration N of the coating is much greater.

ser than N, and then the area of exhaustion mostly lies in the η-conductive material, and that

d =

e N. ^v d
α.

what is the normal schottky barrier term. This approximation can be expected for metal coatings, Coatings of highly conductive semiconductors and adsorbed layers apply, each being adsorbed

609826/1 001

PHB 32 ^ 82 2.12.75

'25550U sr.

Atom or molecule make a contribution equal to an electron charge state supplies.

When the total gate capacitance is C and; a charge q is applied to the gate

V _a = J and
G

e N, ^K 'd ^T C
dq

and the conducting channel will be completely exhausted when

d (q)> ^X 2r,

where r = the radius of the channel.

It is believed that the area of exhaustion turned away from contact does not matter, although of course a gradual exhaustion of the mass of the grain with increasing surface charge must take place. For a layer of zinc oxide grains, using the given Equation for the case of the heterojunction gate layer and some reasonable values for the different ones Parameters the depth of the exhaustion layer (d) can be estimated. For a donor concentration N, =

d 1 ο

10 / cm ³ , a diffusion voltage V = 0.5 ^e V and a value C = 10 for zinc oxide is the value of d

almost 230 A. For a typical zinc oxide powder is 609826/1001

PHB 32482 2.12.75

the mean grain size about 0.25 / um ₅ so that the depth of exhaustion is then almost 10 $ of the grain diameter.

As mentioned above, the gate "cladding" can have various shapes and in order for it to act as a heterojunction the primary requirement is a work function that exceeds the work function of the grain. The work function difference between the two materials is V and, together with N, controls the depletion ^{width d at zero voltage 5} VoIt V. There-

with the gate being able to store charge, the leakage current in the reverse biased state of the gate junction must be small. The value of d must be so large that the tunneling through the barrier is insignificant. The thermal emission current i must also be small, so that V ^> kT. Zener breakdown due to tunneling from the valence band to the conduction band and thermal generation are very unlikely because the band gap of zinc oxide is large (3.2 eV), and tunneling over deep traps is also very unlikely because such deep traps have been found to be one have low concentration.

When operating a three-terminal JFET structure 609826/1001

PHB 32482

an accessible gate contact is obtained. This can, as described, be applied in several layers of powder. but the "floating" gate principle can be cheaper and is already described. When applying this principle, a Number of factors to be considered in a typical single crystal homojunction JFET structure may not occur. These factors include:

(a) Because every JFET with contacts between individual grains has a different geometry, having a different degree of coating, etc., the voltage at which each gate is in the forward direction is biased, and the resulting channel exhaustion for each structure vary.

(b) Since large numbers of such contacts are in series / parallel, the created one is distributed Tension very complex spatially and temporally within the layer.

(c) Because the gate coatings must be relatively non-conductive in order to allow the contacts between the grains are not short-circuited, is an asymmetx-ical Charging of the coating in the area of the contacts with long time constants' to be expected for redistribution .

In the usual JFET with a p-type 809826/1001

PHB 32482

25-550H ² ·. ^{12 75}

Semiconductor gate has the negative gate charge necessary for channel exhaustion in the form of negative space charge due to ionized acceptors. Adsorbed atoms or ions, on the other hand, can form charge save a changed charge level. The charge can also go through some internal transition or an internal polarization of a complex molecule or the bond between one in interaction entered pair of adsorbed species are stored. Hence there are several types of charge storage mechanisms which can be appropriately listed as follows:

(a) Stable - e.g. depletion of free charge carriers in a semiconductor, charging of a non-volatile ion or molecule;

(b) metastable - e.g. modifying the structure or binding on the surface;

(c) unstable - e.g. the adsorption of further atoms or ions from an external source or charging of a volatile ion or molecule.

It can be expected that the first of these mechanisms would show a rapid restoration of balance for a particular disorder such as gate or charge or auffolgender lighting, because it is only about movement of free charge carriers. On the other hand, at 609826/1001

PHB 32482 2.12.75

(b) beef, (c) some such slower processes appear. For image enhancement that requires a fast response, a p-type semiconductor gate would be used ideal on η-conductive grains without deep drops in the structure. The non-liquid adsorbed organic Molecule, such as a dye, may also be suitable, or even some volatile gate coatings, such as adsorbed oxygen, may be sufficient to be fast.

An important difference between civilians The usual single crystal heterojunction and the system formed by coated grains should be emphasized will. The .incident radiation is generally considerably scattered by the grains, and this can be in connection with possibly very thin coatings of the gate material have the consequence that the absorption process over a. Depth is distributed, which is much larger than the normal mass absorption length. However, all absorption steps can still take place close to a collective transition / It also follows that there is radiation Transition areas from inside as well as from outside the grains can approach, so that a heterojunction "window effect" of the known kind to the spectral sensitivity can contribute.

In general it turns out that

609826/1001

PHB 32482-

In the grain systems under consideration, the degree of detection of incident photons for various reasons could be quite low:

(a) Minority carriers generated by photons absorbed in the central parts of grains can be generated, an insufficiently large diffusion length to reach the surface depletion area prior to recombination;

(b) even if they are collected and reach the surface, they eventually neutralize no charge near the interface area at the contact between two grains where you Effect would manifest itself as a change in the conductivity;

(c) similarly, absorption in the coating may not come close enough to the Interfaces to be effective.

The situation is very complex and generalization is difficult. However, it is likely that the degree of collection in the grains is highest when the areas of exhaustion expand completely after charging. It is also advantageous if the coating has sufficient conductivity so that the charge can be redistributed over the whole grain surface can be done. On the other hand, 609826/1001

. PHB 32482

Changes in the surface charge are not scattered over many grains because then image information get lost. For this reason, there are significant advantages when a discount broker Coating of grains is present, which is essentially limited to the grain surfaces that adjoin the interfacial areas at the contacts between individual grains, as is the case with some of the described embodiments is the case.

To operate in a charge storage JFET mode, there must be a conductive channel between the source and drain that is open when the excess charge on the gate is zero. To ensure that this is the case with the contacts between individual grains, the channel radius r in the interface area must be greater than the width d of the exhaustion layer. Although the barrier height (V,) of the transition can be adjusted to a certain extent by the choice of the gate material, one of the easily controllable variables in the expression is the grain carrier concentration, which is a property of the starting material of the grains and by doping or Regulation of the stoichiometry can be controlled. ' The value of r, on the other hand, can be determined by throat growth during a heating treatment corresponding to the first stages of sintering

PHB 32462

255 5G14 2.12.75

action of the layer will be enlarged, which is secondary There may be advantages in that interface areas of adsorbed species are removed and possibly interface damage restored surfaces are eliminated.

The grain size distribution can also be important in various ways. For a given When a voltage is applied to a powder layer, the voltage at a contact between grains clearly depends on the number of grains present between the electrodes. Voltage dependent effects like the the two-terminal gate charging mode described above, therefore, will be in accordance with the expectations for the grain size be sensitive. To keep the operating voltage low for a given electrode spacing hold, the grain size does not have to be too small. The degree of collection for photo-induced electron-hole pairs must be higher for grains that are sufficiently small to allow the radius of the inexhaustible part of the grain is smaller than the minority carrier diffusion length. The total number of contacts between grains must be restored for a satisfactory Uniformity and therefore a small grain size is preferable. One small distribution of particle size could be important in order to determine the number of particles along the short

609826/1001

PHB

ten conduction paths between the electrodes to keep constant. On the other hand, if small grains can between large grains are important for the formation of the channels of intergranular JFET structures greater scattering of the grain size are desired. So the grain size is essentially very important, and the compromise between different factors has to be made for each special case.

It is clear that the inventive Body structures of the type described above in various solid electronic assemblies can be used. In particular, these structures can be used in cases where Control of gain by externally applied means is more important than such Control is through the choice of the starting material. For photoconductive operation, as with photodetector or illustration arrangements, these are Arrangement structures favorable, as can be seen from two further embodiments, their production now will be described.

In making a first embodiment, the means for storing charge are adsorbed oxygen ions and the semiconductor grains are ZnO, but in other similar examples the grains can be CdS, PbO, 609826./100Ί

PHB 32482 25550U 2.-12.75.

other oxides and H-VI compounds exist. That Zinc oxide powder composed of Photox 83 used by the New Jersey Zinc Company for coating Electrofax copier paper Isopropyl alcohol is made by suspending it in a plastic ball mill using agate rollers for 15 to 60 minutes. One Layer of η-conductive ZnO grains with a thickness of about 1 to 5 µm is deposited on a comb-like electrode structure made of a layer of platinum on a substrate of glass or fused silica, in that the Powder from the suspension in a centrifuge with a diameter of 12 "at a speed of 700 to 1000 revolutions / min for one period is spun from 1 to 10 minutes. The big Particles and aggregates are initially removed from the suspension in that at 700 revolutions / Spin for a few seconds without a substrate before the layer is deposited will. An etching treatment of the powder before Milling in 1 $ concentrated HCl in distilled Water for 1 minute is passed to remove any zinc carbonate coating. the Grain size distribution before the etching treatment is at most in the vicinity of 0.4 µm and this value becomes 609826/1001

PHB 3? Ji

reduced to about 0.3 μm by etching.

The layer shows strong photoconductivity at this stage and normally shows an increase in conductivity of 5 t> i ^s 6 orders of magnitude when illuminated with an unfiltered 250 W low-pressure mercury vapor lamp at a distance of 40 cm in the free atmosphere with a rise time of about 0.1-0.5 seconds and a fall time of 10-50 seconds. To 200 ° C for about one hour, the fall time is extended to many hours by drying in an oven at 50 ⁰ C for several days or at 100th By heating to 300 - 800 ° C in the air, the fall time is reduced to a few tens of milliseconds, which can be attributed to the removal of remaining surface coatings from the grains. For arrangements treated at higher temperatures of 600 to 800 ° C, the dark current is also significantly increased.

The application of a voltage pulse with

a rise and fall time of a few milliseconds at such a ZnO layer in the air generally causes a considerable reduction in the conductivity of the layer. Immediately after deposition and partial drying of the layer at room temperature for about an hour, the dark current is 609826/1001

PHB 32482

too low for the effect of a voltage pulse to be noticeable. After illumination, provided that the drop in the photocurrent is sufficiently slow that is, before the heating treatment at 300 to 900 ⁰ C, a voltage pulse between 200 and 400 V with a duration of 50 to 100, a reduction msec of the conductivity of up to three orders of magnitude bring about. After the heating treatment at high temperature, a pulse of 150 V with a duration of 5-10 msec will bring about a decrease in conductivity of two orders of magnitude from the increased steady dark conductivity level.

In all cases, the lighting offsets at a wavelength equal to or slightly shorter than the absorption constant of ZnO (i.e. between 3700 and 4100 Α) brings the conductivity back to its normal photoconductive level. In the dark, the reduced conductivity level slowly increases again towards the normal dark level in a period between a few hundred milliseconds and several minutes. The increase in conductivity from lighting after pulsing is almost that Product of the intensity and the exposure time proportional, i.e. that an integration takes place.

609826/1001

The layer can be treated in this way in oxygen or air. In nitrogen the above-mentioned effect of the voltage pulse disappears after a few minutes. Venn the layer of When exposed to ambient air, the rapid photoconductive response achieved is increased Dark conductivity and sensitivity to short low voltage pulses gradually in one Period of several hours can be changed in such a way that the behavior described above before the treatment occurs at high temperature.

The ZnO layers mentioned can be produced in that a suspension of the powder in a solution of a binder such as Pliolit (a polystyrene-butadiene copolymer made by Goodyear Rubber Company) in a solvent such as xylene onto the comb-like electrode structure is injected. Such layers have long photoconductive decay times of up to minutes or hours, but also a sensitivity to voltage pulses that is the same as that above for a Layer with no binder prior to the high temperature heat treatment is. This heating treatment cannot take place because of the pliolite binder would decompose.

6098 26/1001

PHB 32 ^ 82

In making a second embodiment in which the grains are also made of n-type zinc oxide, the means for forming rectifying barriers are surface coatings of the opposite conductivity type on the
Grains. The same procedure for forming the
Layer is used up to and including the high temperature heating treatment between
300 and 900 ° C. The layer is then immersed in a solution of copper sulfate in water using 0.01 to 10 g of CuSO. immersed per liter of distilled water. After washing with distilled water
the layer is immersed in a sodium hydroxide solution with a pH of 11 and hydrazine hydrate is added to form the CuSO. to reduce Cu "0. The Cu ₂ O is deposited on the ZnO grains and a light brown layer is obtained.

Almost 0.25 g CuSO. per liter of water there is a Cu ^ O / ZnO weight for a weight ratio of about $ 0.3. This will increase the dark conductivity
of the ZnO layer in the absence of adsorbed oxygen by about four or five orders of magnitude compared to an uncoated layer. ■ -

Such layers show a similar one
Sensitivity to a voltage pulse as above

6098 26/100 1

^PHB 32482 2.12.75

for the uncoated layers in the air. If the Cu "O coating is too thick (eg more than 1.5% by weight calculated on the ZnO weight), the conductivity is too low to observe the effect of the pulse. If the Cu ₅₁ O is too thin (eg, less than 0.05 wt. ^ O calculated on the weight of ZnO), the conductivity is so high that the voltage pulse causes a destructive high current pulse flows.

In particular for the thinner coatings, surrounding gases, for example oxygen, can still be adsorbed on the grains and bring about the effects described in the previous embodiment. In order to make the effect of the CUpO coating noticeable alone and to avoid degradation as a result of HpO, CO, etc., encapsulation or filling of the layer is desirable. This can be done with the aid of an inert material, such as polyethylene wax or silicone oil, which is transparent to the radiation to which the layer is sensitive. In the case of coatings of, for example, Cu ₂ O with a band gap that is much smaller than that of ZnO, the sensitive area shifts into the visible area.

When producing another embodiment which is a modification of the last described 609826/1001

PHB 32482

In this embodiment, the zinc oxide layer is immersed in an aqueous solution of copper chloride (CuCl) and neutralized hydrazine hydrate, a pH of almost h being obtained. The copper is mistaken for the zinc in order to obtain a p-type copper oxide coating on the η-type zinc oxide grains. Such layers show a similar sensitivity to a voltage pulse as the layers described above. Non-binder layers made from zinc oxide grains coated with Cu2O by the second method described show a low dark conductivity in the air equal to that for uncoated layers. In the vacuum, however, only a partial restoration of the conductivity is observed, depending on the thickness of the CupO layer. The CupO / ZnO weight ratio of the layers can be measured as a function of the CuSO. Concentration using absorption spectroscopy. The exact thickness of the Cu_O layer is not known, but it must be a small fraction of the ZnO grain diameter. When increasing the Cu _? 0 concentrations in the layer reduce the photoconductivity in the air and in a vacuum by up to three orders of magnitude. The dark conductivity in vacuum also decreases, while the dark conductivity in air increases

609826/1 OQ 1 '

PHB 32 * 1-82 2.12.75

is low to be measured.

For the deposition of the zinc oxide powder layers, centrifugation has been found to produce a Suspension of the powder granules in polyvinyl alcohol using a conventional photoresist centrifuge device results in greater evenness, packing and reproducibility. It is necessary, then to heat the polyvinyl alcohol in air, after which degassing in a vacuum with lighting he follows. This results in a greatly increased dark current in the air, from which it can be seen that by this method of forming the layer larger surfaces of the contacts between individual Grains are obtained than can be obtained when the layers are formed by spraying or centrifugation.

Details of the manufacture of other powder layers required for assembly structures with n-type Zinc oxide grains are suitable will now be described. Zinc oxide powder, which, as in the previous Embodiments made of Photox 83, is subjected to an etching treatment by grinding in a ball mill. 10 g of the powder with 30 ml Was-ST32? are ground for 30 minutes in a ball mill and then with continued stirring made up a suspension of 200 ml. 2.5 ml con-

609826/1001

PHB -32 ^ 82-2.12.75

Centered hydrochloric acid is added and the flow is continued for 1 minute. The acid is then filtered off and the powder is then washed with 1 liter of distilled water and then thoroughly dried. 2 g of the etched ZnO is ground in a ball mill with 5 nil of h by weight, ^ - strength polyvinyl alcohol in water, h ml of ethanol and h ml of methanol for 2 hours. The mixture is then applied dropwise to a comb-like electrode system made of aluminum or platinum on a substrate made of fused silica or glass until the surface of the substrate is covered. The mixture is then centrifuged using a photoresist centrifuge device, for example at 4000 revolutions / min for a substrate of 17 mm × 17 mm and at 1700 revolutions / min for a substrate of 50 mm × 50 mm. This process results in a layer with an average thickness of about 1.5 µm. In order to obtain thicker layers, more settling and centrifugation steps, each lasting about 1 minute, can be carried out. The layer is then baked in air at 400 ° C. for one hour. A resulting residue on the layer, the identity of which is not established, is produced by irradiating the sample with ultraviolet light

609826/1001

PHB 32482

removed for several minutes in a vacuum of about 10 Torr. After this treatment it is found that the conductivity and the photosensitivity of the sample have increased by up to four orders of magnitude. The sample is then coated with a dye having p-type conductivity properties, which dye is a material commercially available as Eosin Bluish or Eosin Yellowish or Rose Bengal, which coating process, in one example, by immersing it in a solution of the dye for 1 minute takes place in water, which forms 10 ^ of the saturated concentration. The sample is then removed from the resulting solution, washed in distilled water and dried thoroughly. Various attempts have been made using Rose Bengal dye coatings of various thicknesses. The thickest of the dye coatings gave effects that were found to be caused by the dye alone. For the very thin coatings, the decrease in specific resistance after irradiation with an ultraviolet lamp in air and in a vacuum was the same as that for an uncoated layer. The sensitivity of the photoconductivity became in the area of the absorption band of the dye as the thickness of the 609826/1001

PHB 32482

Dye coating gradually increased. The main effect of the dye was a significant decrease in the decay time of photoconductivity in air as well in a vacuum. There was also a greatly reduced response time when re-exposure to air in the dark observed.

Some experimental details of methods for applying a coating are now set out p-type lead iodide on the grain surfaces η-conductive zinc oxide in a body with one made by the method of the previous example Powder layer given. In a so-called "wet-chemical" process, the powder layer first pre-wetted by placing it in distilled water and then in a solution (0.33 M) of Pb (NO ') is immersed for 2 minutes. The sample is then washed and immersed in a solution (0.66 Μ) of potassium iodide for 30 seconds. The probes are then dried.

In a second process, the lead iodide is formed by precipitation at room temperature from a solution (0.1 M) of Pb (NO_) and a solution (0.2 M) of potassium iodide. After a washing and drying step, 0.5 g of the lead iodide powder is attached by grinding in a ball mill with 30 ml of propan-2-ol (IPA). The sus- 6098 26/1001

PHB 32482 2.12.75

25550U

pension is made for 15 seconds with 1800 revolutions / Min centrifuged and then the remaining liquid is poured through a pipette onto the zinc oxide powder layer applied to the substrate. After equilibration, the sample is set at 1500 for 10 minutes Centrifuged revolutions / min. The liquid is siphoned off and the sample is dried.

In another method, 2 g of Bleijodidpulvers prepared as described in the previous example, with a ¹ solution of 12.5 $ Pliolit ground in a ball mill for 5 B in 13 ml of xylene. It is then sprayed onto the zinc oxide powder layer until the layer turns a light brown color. The sample is then dried at 50 ° C. for two and a half hours.

Another method is the lead iodide onto the zinc oxide powder layer by vapor deposition applied in a vacuum. 0.05 g of lead iodide is in one Tungsten boat attached, which is in the Vacuum chamber at a distance of 200 mm from the Zinc oxide powder layer is located on the substrate and is heated to about 500 ° C. A suitable deposit can take place even when the zinc oxide layer on the substrate is at room temperature is located.

In another example where lead

609820/1001

PHB. "32482-

oxide grains are used which are originally conductive and have a size between 0.5 and 1.0 μm, the powder bodies are baked out at 400 ° C. in air for one hour in order to convert them into p-conductive material. 2.8 g of the powder produced is milled for one hour with 5 ml h $ strength polyvinyl alcohol in water, 4 ml of ethanol and h ml of methanol. Then it is centrifuged at 500 revolutions / min and dried. After baking and lighting in a vacuum, the lead oxide layer on the electrode system and substrate can be coated with an η-conductive organic dye, e.g. a dye commercially available as Rhodamine B, by adding 10% of the saturated concentration to a solution of the dye in water forms, is immersed.

Other means of coating grains such as vapor transport of the coating material, deposition of metal vapor and subsequent oxidation, reactive vapor deposition, electrolytic deposition, electroless deposition, can be used. Other coating materials, such as PbO, ZnTe, CdS, CdSe, organic semiconductor materials (including Dyes) can be used and deposited in a number of ways.

609826/1001

PHB 32482.

Two further embodiments of the invention will now be described with reference to FIGS. 7 and 8. The arrangement shown in partial cross-section in FIG. 7 is a field effect controlled image intensifier panel with a glass substrate 31 with a thickness of about 5 mm on which there is a comb-like electrode pattern made of aluminum layers 32 with a thickness of 2000 A ° and a width of 4θ / µm and semipermeable tin oxide electrode layers 33 with a thickness of about 1 / µm and a width of 300 / µm, the distances between the electrode layers 32nd and 33 being 250 / µm. On the glass substrate 31 and as a cover for the electrode layers 32 and 33, there is a direct current electroluminescent layer consisting of zinc sulfide grains with a copper sulfide coating in an epoxy binder. The layer 3h has a thickness of about 10 to 15 µm. On the layer 3h is a photoconductive layer 35 with a thickness between 1 and 5 / µm, which consists of a layer of contacting zinc oxide powder grains, with a coating at least on the surface areas of the powder grains which adjoin the interface areas at the contacts between individual grains Lead iodide is present, and where the powder layer - including the

609826/1001

PHB 32482

coated grains - made by a process of the type described above.

When this "two-clamp" arrangement is operated, the zinc oxide powder layer is charged by a mechanism described with reference to FIGS. 300 to 100 V are periodically applied over the comb-like electrode layers 32 and 33 with a duration of 1 to 50 msec. Due to the geometry of the layer 3 ^ and the electrode layers 32 and 33 of the main current flow between adjacent electrode layers 32 and 33 is across the layer 3 ^ - and then laterally held in the Zinkoxidpulverschicht 35, wherein the main current conduction paths in the layer 35 across the interface areas to extend the contacts between individual grains and, in a preferred operating mode, the charging pulse is of sufficient size to cause the said paths to be blocked. Radiation originating from the scene to be observed and incident on the upper surface of the zinc oxide layer 35 has the effect already described when it is absorbed in the layer 35, which effect is that the grains locally in the interface regions at the contacts between individual Grains around a

609828/1001

PHB 32482

An amount can be discharged, which depends on the strength of the incident radiation and the time of incidence after the previous charging pulse. Applying a DC voltage of about 200 to 300 V of the correct polarity between the electrode layers 32 and 33 induces DC electroluminescence in the layer 3 ^ in the vicinity of the positive electrode layer 33. The density is determined by the conductivity of the adjacent part of the zinc oxide layer 35 via the main current conduction paths in this layer 35, through which the current must pass through the adjacent electrode layers 32 and 33. The conductivity in this part of the layer 35 depends on the state of charge at the contacts between individual grains, which is determined by the local strength of incident radiation after the application of the charging potential pulse. As a result of the rectifying character of the direct current electroluminescent layer after a "voltage-shaping" treatment and the higher degree of electroluminescence of this layer, when the readout voltage is applied in the corresponding reverse direction, it is advantageous to apply the reset pulse for the zinc oxide with such a polarity that the zinc sulfide layer is biased in the forward direction. Then, firstly, occurs

80982671001

PHB 32482-

25550 H. ² x ¹² - "

a smaller voltage drop across the zinc sulfide layer and second, less light emission from the zinc sulfide layer during the reset pulse on.

In a typical image intensifier panel, the area is 15 cn χ 15 cm. This type of voltage pulse reset panel therefore only needs to have two electrodes to which both the reset pulse and the readout voltage are applied. The choice of a direct current electroluminescent layer for the output instead of an alternating current electroluminescent layer is preferred because the series impedance of an alternating current electroluminescent layer, for example made of zinc sulfide, may make it impossible to apply a sufficiently large reset charge pulse. In any case, the duration of the reset charge pulse must be a small fraction of the image period and each emission from layer 3h when this pulse is applied must be relatively small compared to the total emission during the image period. Optical feedback from the visibly emitting electroluminescent layer to the zinc oxide layer, which is sensitive to the near ultraviolet, is not essential. If, however, instead of zinc oxide grains, e.g. lead oxide

60982671001

PHB 32482

grains or lead iodide grains are used it is essential to have optical feedback through an opaque layer between the input and output stages to avoid. Method of obtaining the necessary transverse conductivity, however the use of material with lateral conductivity, such as avoiding graphite, is known.

In the embodiment now to be described with reference to FIG. 8, some of the difficulties which arise when the zinc oxide layer is reset by applying the pulse in series with the electroluminescent layer are at least partially avoided. The arrangement shown in partial section is a field-effect-controlled image intensifier panel with a glass substrate 41 with a thickness of 5 »0 mm, a semipermeable electrode layer made of tin oxide with a thickness of 1.0 μm, a conventional alternating current electroluminescent layer made of zinc sulfide with a thickness of 10 to 15 / um, a zinc oxide powder chi chrb with a thickness of about 1 to 5 / um and with the shape described, wherein the Kormoberflächen are coated with a layer of a p-type semiconductor material, such as lead iodide, and comb-like electrode layers h6 and 4 7 from Tin oxide, which in the section shown has a width of 40 μm and an opposite

609826/1001

PHB 32482

have a lateral spacing of 40 / .mu.m. When this arrangement is in operation, the zinc oxide layer is charged with the aid of voltage pulses of 250 V and a duration of 20 msec, which are applied via the comb-like electrodes 46 and 47. The output change tr omelektrodenlumineszenz-image reproducing apparatus is thereby obtained that an AC voltage of 500 V RMS between dex ⁿ electrode layer 42 and the electrode layers 46 is applied and 47th In this arrangement the reset pulse is applied in the plane of the layer to control the conductivity of the layer through the thickness of the layer.

It stands to reason that the sensitivity of the image intensifier panels of FIGS. 7 and 8 represented by the impedance mismatch influenced between the zinc oxide and zinc sulfide layers will be. The adaptation and thus the sensitivity can be improved as a result, that the conductivity of the zinc oxide layer in the work area is enlarged, e.g. by heating the powder layer to a higher temperature, which is subject to a sintering temperature in the formation of the desired configuration of the contacts between each Grains or by increasing the carrier concentration. The application of an alternating current

6098 26/1001

PHB 83 ^ 82

electroluminescent layer instead of a direct current electroluminescent layer facilitates improved customization.

Arrangements according to the invention which contain at least one layer of semiconductor grains, can take many different forms. As already described, you can then in imaging arrangements and for photodetection purposes can be applied. Another application is in electrophotography, being a charged one Layer after exposure can be exposed to toner particles. Other applications where the Exhaustion of the main current conduction paths in the layer by one of the above-mentioned adsorbed species on the Grain surfaces takes place, lie in the gas detection and possibly in gas transport, as mentioned above. Within the scope of the invention, however, there is also a semiconductor arrangement in the form of a simple one photoconductive layer comprising the grains of semiconductor material with the said intergranular Contacts and associated means for storing charge at least locally close to the interface regions at the contacts between individual grains. One such by one Element-formed powder photodetector is fundamentally more versatile than known photoconductors,

609826/1001

PHB83482

■ 25550H - ² - ^{12 75}

because when operating in a charge storage mode the possibility of an external regulation of the amplification and the response time exists »

Other possible areas of application of an arrangement structure according to the invention lie in (a) Variable voltage capacitors, the capacitance of a powder layer by charging the surface of coated grains can be controlled; printed active and passive micro-scarf processing parts, starting from semiconductor powder layers; (c) photocathodes with a high gain, the one photoconductor powder layer of the new structure in series with an electron-emitting one Layer included; (d) targets for vidicon camera tubes with a high gain; (e) Imager devices employing field effect conductivity control based and have the form in which a relatively low energy electron beam is used to selectively to address a pre-charged photoconductive layer of powder grains in series with an electroluminescent layer is arranged; (f) adjustable voltage-dependent resistances, which are based on semiconductor powder layers, with a pre-setting of the properties can thereby be obtained that the contacts

6 09826/1001

PHB 32H82 2.12.75

are charged between individual grains; (g) electronic switches on the setting j (h) electronically controlled catalysts are based on impulses of the conductivity of a powder layer for chemical process control, being catalytic Effectiveness in connection with gas absorption and desorption is controlled by the fact that a powder layer is biased, and (i) storage arrangements that have a changed conductivity as a result use of charge storage.

609826/1001

Claims (1)

PHB 32482 25550η ² ; ¹² ; ⁷⁵ Claims ; (1. J semiconductor device, characterized in that that it contains an inhomogeneous body in which the semiconductor material body is present and the contact between adjacent grains is such that there is continuity in the interface areas exists between the masses of the adjacent grains, the main conduction paths being in the body extend within the grains over the interface areas at the contacts between individual grains, and wherein under thermal equilibrium conditions at rest, said conduction paths are not completely depleted while providing means of storing charge within the body the surfaces of the grains are present, which are at least locally attached to the interface regions on the. Contacts between individual grains border on the control of the electrical conductivity at least part of the body through surface field effect creation the conduction paths between adjacent grains in the interface areas at the contacts to allow between individual grains in said body part. 2. Semiconductor arrangement according to claim 1 _f, characterized in that the arrangement is set up for operation in a charge storage mode and 609826/1001 PHB 32 ^ 82 Contains electrode means, with the help of which a suitable Potential pulse for charging the body in the vicinity of at least some of the contacts between individual grains and to derive an output signal that at least the electrical conductivity of a part of the body, which is determined by the charge stored in it will. 3. Semiconductor arrangement according to claim 1 or 2, characterized characterized in that the means of storing charge that are attached to the inside of the body Surfaces of the grains are located at least locally on the interface areas at the contacts border between individual grains, rectifying transitions at or near the named ones Form surfaces of the grains. k. Semiconductor device according to claim 3 »characterized in that the distribution of the grains in the body and the configuration of the rectifying barriers are such that when a potential difference is applied between adjacent grains via electrode connections on the body, the electric field distribution in the interface regions at the contacts between individual grains is changed, whereby charge at least locally in the body in the vicinity of the interface areas at the 609828/1001 PHB 32482 2.12.75 2555OH Contacts between individual grains is saved, 5. Semiconductor arrangement according to claim 3 or 4, characterized in that electrode means the body are provided which in an independent manner the to the means of forming the rectifying Control transitions applied potential. 6. Semiconductor arrangement according to one of claims 3 to 5 »characterized in that the rectifying Transitions within the grains are formed by transformed surface layers, which border on the interface areas at the contacts between individual grains, these Surface layers one that of the main mass of the grains, in which the main current conduction paths extend, have opposite conductivity type. 7 · Semiconductor arrangement according to one of claims 3 to 5 »characterized in that the rectifying Transitions are formed by a material that is applied to the grain surfaces, which at least locally to the boundary areas limit the contacts between individual grains. 8. Semiconductor arrangement according to claim 7 »thereby characterized in that the attached material is in the form of a coating layer which is attached to the grain surfaces, which little- 609826/1001 25550H PHB 32h82 2.12.75 at least locally, to the interface areas at the contacts border between individual grains. 9. Semiconductor arrangement according to claim 7 »characterized in that the material as a Material of relatively high specific resistance is present that almost fills the spaces between the grains in the body. 10. Semiconductor arrangement according to one of the claims 7 to 9 »characterized in that the material present at least locally on the grain surfaces and the grains form rectifying pn homojunction. 11. Semiconductor arrangement according to one of claims 7 to 9 »characterized in that the at least Material present locally on the grain surfaces and pn heterojunctions rectifying the grains form. 12. Semiconductor arrangement according to claims 8 and 11, characterized in that the body contains grains of η-conductive zinc oxide, the at least are locally coated with a material selected from the group consisting of p-type Lead iodide, p-type lead oxide, p-type Copper oxide and p-type zinc telluride is formed. 13 · Semiconductor arrangement according to claims 8 and 609826 / 1.001 . PHB 32482 25550 U ^{2 12 75} 11, characterized in that the body contains grains of p-conductive lead iodide which are at least locally coated with η-conductive zinc oxide or n-conductive
Are coated with lead oxide. 14. Semiconductor device according to. Claims 8 and 11, characterized in that the body contains grains of η-conducting cadmium sulfide which are at least locally coated with a material selected from the group consisting of p-conducting
Copper sulfide, p-type zinc telluride and p-type lead iodide is formed. 15 · Semiconductor arrangement according to claims 8 and 11, characterized in that the body contains grains of p-conductive zinc telluride which are coated at least locally with a material selected from the group consisting of η-conductive cadium sulfide, η -conductive zinc selenide, η-conductive
Zinc oxide and η-conductive lead oxide is formed.
16. Semiconductor arrangement according to claims 9
and 11, characterized in that the body
contacted grains of η-conductive zinc oxide or
η-conductive cadmium sulfide and the rooms
between the grains are almost filled with p-type zinc telluride of high specific resistance.
17 · Semiconductor arrangement according to claims 9 and 6098 26/100 1 PHB 32482- 25550H ² × ^12-75 11, characterized in that the body contacted Contains grains of p-type zinc telluride and the spaces between the grains almost with a Material of high specific resistance are filled, which is selected from the group made by nleitendes Cadmium sulfide and η-conductive zinc selenide is formed. 18. Semiconductor arrangement according to one of claims 7 ″ to 9f, characterized in that the at least Material locally present on the grain surfaces is a semiconductor material with the same conductivity styp like the material of the grains, but from of a different composition. 19 .. Semiconductor arrangement according to Claims 8 and 18, characterized in that the body has grains of η-conductive zinc oxide, on which a coating forming a rectifying heterojunction made of η-conductive cadmium sulfide or n-conductive zinc selenide is attached « 20. Semiconductor arrangement according to Claims 8 and 18, characterized in that the body has grains made of p-type zinc telluride, on which a rectifying heterojunction forming coating of p-type copper oxide is attached. 21, semiconductor arrangement according to claim 9 »characterized characterized that the body consists of grains 603826/1001 PHB -32 ^ 82. holds, which are at least locally coated with an organic dye. 22. Semiconductor arrangement according to one of the claims 1 to 31 characterized in that the means for Storage of charge at least on the surface parts of the grains that adjoin the interface regions delimit the contacts between individual grains, contain at least one adsorbed gas species, selected from the group formed by atoms, ions and molecules, the electrochemical Potential of the adsorbed species exceeds or falls below that of the material of the grains, in Depending on whether the grains consist of n-conducting or p-conducting material. 23. The semiconductor device as claimed in claim 22, characterized in that the grains are made of n-conducting Zinc oxide and the adsorbed species consists of oxygen ions. 2k. Semiconductor arrangement according to Claim 8 or one of Claims 12 to 15 »characterized in that, in addition to the coating on the grain surfaces, the means for storing charge also contain adsorbed gas ions, molecules or atoms on the surface of the applied coating. 25. The semiconductor device according to claim 2k, characterized in that the grains of zinc oxide 609826/1001 PHB 32h82 25550K ² " ¹² " ⁷⁵ ■ Μ: insist that on the surfaces that at least adhere to the interface areas border on the contacts between individual grains, a coating of p-type conductive Contains lead iodide, on the surface of which there are adsorbed oxygen ions, 26. Semiconductor arrangement according to claim 8 or one of claims 12 to 15 »characterized in that that next to the coating on the grain surfaces the means for storing charge further contain gas ions, molecules or atoms that are inside of the coating material have diffused, 27. Semiconductor arrangement according to one of claims 1 to 26, characterized in that the body is in the form of a layer with a thickness of at least a plurality of grains. 28. Semiconductor arrangement according to one of claims 1 to 27 »characterized in that the arrangement is an image intensifier panel whose body containing the contacted grains is in the form of an input photoconductor layer for collecting incident radiation and on an output electroluminescent layer is appropriate. 609826/1001 Blank page