TWI536596B - Materials, fabrication equipment, and methods for stable, sensitive photodetectors and image sensors made therefrom - Google Patents

Description

Materials for stable, sensitive photodetectors, manufacturing equipment and methods, and image sensors made therefrom Related application

This application is part of the continuation of U.S. Patent Application Serial No. 12/106,256 (filed on April 18, 2008).

This application claims the benefit of U.S. Patent Application Serial No. 61/082,473, filed on July 21, 2008.

This application claims the benefit of U.S. Patent Application Serial No. 61/154,751 (filed on Feb. 23, 2009).

Technical field

The present invention generally relates to optical and electronic devices, systems and methods comprising optically sensitive materials such as nanocrystals and other optically sensitive materials, and methods of making and using such devices and systems.

background

Optoelectronic devices, such as image sensors and photovoltaic devices, can comprise optically sensitive materials. The exemplary image sensor includes means for sensing and reading electronic and multiplex functions. For some image sensors, optically sensitive phosphor diodes and electronic devices can be formed on a single germanium wafer. Other exemplary image sensors may use a different material, such as InGaAs (for short-wave IR sensing), or amorphous selenium (for x-ray sensing) for sensing (photon conversion to electrons) functionality. An exemplary photovoltaic device includes a solar cell that uses a crystalline germanium wafer for photonicization into electrons. Other exemplary photovoltaic devices may use a different material layer (such as an amorphous or polycrystalline germanium) or a separate material for photon conversion to electrons. However, such image sensors and photovoltaic devices are known to have several limitations.

An optically sensitive device comprising: a first contact and a second contact, each having a work function; an optically sensitive material between the first contact and the second contact, the optical The sensitive material comprises a p-type semiconductor, and the optically sensitive material has a work function; the circuit is configured to apply a bias voltage between the first contact and the second contact; the optically sensitive material The number of work functions is at least 0.4 eV greater than the number of work functions of the first contact, and is also at least 0.4 eV greater than the number of work functions of the second contact; the optically sensitive material has a ratio The bias voltage is applied to the first contact and the second contact when the electronic operation time of the electron from the first contact to the second contact is greater; the first contact provides injection and blocking of electrons The hole is captured; and the interface between the first contact and the optically sensitive material provides a surface recombination rate of less than 1 cm/s.

Incorporated for reference

Each of the patents, patent applications, and/or announcements referred to in this specification are hereby incorporated by reference in their entirety as if each patent, patent application, and/or Enter the level for reference.

Simple illustration

Figure 1 shows a material stack of one embodiment.

Figure 2 is a cross-sectional view showing a stack of materials on a portion of a pixel of an embodiment.

Figure 3 is a cross-sectional view showing a stack of materials on a pixel of an embodiment.

Detailed description

An optically sensitive device is described below. The device includes a first contact and a second contact, each having a work function and an optically sensitive material between the first contact and the second contact. The optically sensitive material comprises a p-type semiconductor and the optically sensitive material has a work function. The device includes a circuit for applying a bias voltage between the first contact and the second contact. The number of work functions of the optically sensitive material is at least 0.4 eV greater than the number of work functions of the first contact and is at least 0.4 eV greater than the number of work functions of the second contact. The optically sensitive material has an electron lifetime greater than the electron transfer time from the first contact to the second contact when the bias voltage is applied between the first contact and the second contact. The first contact provides electronic injection and resists hole extraction. The interface between the first contact and the optically sensitive material provides a surface recombination rate of less than 1 cm/s.

An optically sensitive device is described below. The device includes a first contact, an n-type semiconductor, an optically sensitive material comprising a p-type semiconductor, and a second contact. The optically sensitive material and the second contact each have a lighter work function than 4.5 ev. The device includes a circuit for applying a bias voltage between the first contact and the second contact. The optically sensitive material has an electron lifetime greater than the electron transfer time from the first contact to the second contact when the bias voltage is applied between the first contact and the second contact. The first contact provides electronic injection and resists hole extraction. The interface between the first contact and the optically sensitive material provides a surface recombination rate of less than 1 cm/s.

A photodetector is described below. The photodetector includes a first contact and a second contact, each having a work function. The photodetector includes an optically sensitive material between the first contact and the second contact, the optically sensitive material comprises a p-type semiconductor, and the optically sensitive material has a work function. The photodetector includes a circuit for applying a bias voltage between the first contact and the second contact. The number of work functions of the optically sensitive material is at least 0.4 eV greater than the number of work functions of the first contact and is at least 0.4 eV greater than the number of work functions of the second contact. The photodetector includes a circuit for applying a bias voltage between the first contact and the second contact. The optically sensitive material provides a responsivity of at least 0.8 A/W when this bias is applied between the first contact and the second contact.

In the following description, numerous specific details are introduced to provide an understanding of the embodiments of the systems and methods. However, those skilled in the art will appreciate that such embodiments can be practiced without one or more of these specific details or by other components, systems, and the like. In other instances, well-known structures or operations are not shown or described in detail to avoid obscuring the embodiments.

The image sensor is combined with a photodetector array. These photodetectors sense light and convert it from an optical signal to an electrical signal. The description of the characteristics of the lower coefficients, any one or combination of which can be found in the photodetector of an embodiment; however, the embodiments herein are not limited thereto.

The photodetector of an embodiment can be easily connected to other circuits related to the image sensing function (such as a circuit for storing charge, a circuit for delaying the amount of signals to the periphery of the array, a circuit for manipulating such semaphores in the analogy field, The analogy is converted into a digital signal circuit, and the image-related data is processed into a digital domain circuit).

The photodetector of an embodiment provides maximum sensitivity to light within a band of interest for a wavelength band spectrum or with a low dark circuit. Sensitivity is used to quantify the measured signal noise ratio (SNR) of a particular illumination. The signal system is the largest when the device's responsiveness, quantum efficiency, or gain is maximized. When the random variation in the electronic signal is minimal, the noise system is the smallest and is subject to the limits imposed by the natural variations in current and voltage at a particular temperature. Correspondingly, the noise of the background signal and other uncontrolled or unpredictable changes are generally minimized when the number of dark circuits is minimal.

The photodetector of an embodiment provides a relatively fast response time when compared to conventional photodetectors formed using conventional processing methods. Applications such as video imaging and shutterless still image capture typically require a substantially complete change in semaphore in response to less than 100 milliseconds (10 frames per second), or less than 33 milliseconds (30 frames per second). , or even a transient photodetector within 1 millisecond (1/1000 second exposure to a still image).

The photodetector of an embodiment provides for detecting a wide range of light intensities in a manner that can be conveniently processed by conventional electronic circuitry. This feature is known for providing a high dynamic range. One method of providing a high dynamic range is to compress the measured electronic response as a function of incident light stimulation. This compression can be referred to as sublinearity, i.e., with a reduced slope nonlinearity, and the electrical signal is dependent on the incident intensity. The high dynamic range can also be facilitated by the use of a photodetector whose gain can be controlled, such as by selecting a voltage deviation known to produce a particular gain.

The photodetector of an embodiment provides for identification of different spectral bands along the electromagnetic radiation. Of particular interest are x-rays, ultraviolet light, visible light (including blue, green, and red), near-infrared, and short-wave infrared bands.

The following are described in various applications for generation, integration (e.g., with circuitry), and methods and processes for developing an upper surface photodetector or photodetector array.

The photodetector and photodetector array described herein can be easily combined with image sensor circuits and other parts of the system by, for example, spin coating, spray coating, drip coating, sputtering, physical vapor deposition, chemistry Vapor deposition, and self-assembly methods are integrated. Embodiments include replacing a shorter ligand with a ligand that is passivated on the surface of the nanoparticle, which provides proper charge carrier mobility once the film is formed. Embodiments include solution phase replacement that enables a smooth morphology film to be used to achieve an image sensor with acceptable uniform dark current and light responsiveness on an array.

The photodetectors described herein provide relatively maximum sensitivity. It maximizes the signal by providing a light guide gain. The value of the light guide gain ranges from 1 to 50, resulting, for example, in the range of visible wavelengths from 0.4 A/W to 20 A/W. In an embodiment, the photodetector described herein minimizes noise by fusing the nanocrystalline core to ensure substantially no noise degradation between the particles constituting the optically sensitive layer through which the current flows. Electrical communication. In an embodiment, the photodetector described herein minimizes the dark current by minimizing the net doping of the active layer, thereby ensuring that the dark carrier density and thus the dark conductivity of the optically sensitive materials are minimized. . In an embodiment, the photodetector described herein minimizes dark current by providing an electrode that is electrically coupled to the nanocrystalline layer (which blocks, for example, a carrier, which may include a balanced primary carrier). In embodiments, cross-linking molecules are used which utilize chemical functionality to remove oxides, sulfates, and/or hydroxides that cause p-type doping. Thus, in an embodiment, a more essential or flat n-type optically sensitive layer can be provided resulting in a reduced dark current. In embodiments, many steps of quantum dot synthesis and/or processing and/or device packaging can be performed in a controlled environment, such as Schlenk line or Glove Box; and the optically sensitive layer can be used substantially impermeable A layer such as an oxide, an oxynitride, or a polymer such as polyxylene, or an epoxide is encapsulated to avoid significant penetration of the reactive gas, such as oxygen or water, into the optically sensitive layer. In this way, combinations of properties such as gain, dark current, and hysteresis can be maintained over the life of an image sensor.

The photodetector described herein provides a time domain response that can be as fast as about sub-100 milliseconds, sub-30-milliseconds, and sub-1-milliseconds. In an embodiment, this can be achieved by providing a capture state that provides gain (and provides persistence) associated with the optically sensitive layer, which can capture at least one carrier only for a duration such as 100 milliseconds, 30 milliseconds, or sub-1 Limited time in milliseconds. In an embodiment, the PbS nanoparticle is decorated with PbSO3 (oxide of PbS), exhibiting a capture state lifetime of about 20-30 milliseconds, providing a transient response suitable for many video imaging applications. In an embodiment, the photodiode system is provided primarily as a colloidal quantum dot layer, and two electrical contacts having distinct work functions are used to contact the active layer. In an embodiment, the dark current can be minimized by operating the device without appreciating an appreciable external voltage deviation. In embodiments, a cross-linking moiety (such as phenyldithiol, bidentate) can be used to shift In addition to and/or passivation, certain capture states that are present or developed in such materials.

The photodetector described herein provides a dynamic range of acceleration by generating a linear dependence of an electrical signal, such as a photocurrent. In the low to medium intensity range, the captured state can be filled and escaped after a moderately persistent (or captured state) lifetime (such as 30 milliseconds). At higher intensities, these captured states are substantially filled, and therefore, the charge carriers encounter a shorter lifetime (or residence time) corresponding to a lower differential gain. Thus, such devices exhibit a substantially fixed gain in the low to medium intensity range, after which the gain at a higher intensity is moderately reduced. In other words, at low to medium intensity, the photocurrent is approximately linearly dependent on intensity, but at higher intensities, the photocurrent exhibits a sub-linear similarity to intensity. In an embodiment, the light guide gain is provided by a photodetector depending on the deviation applied to the device. This occurs because the gain system is proportional to the carrier lifetime divided by the carrier transfer time, and the transfer time is inversely proportional to the applied field. In an embodiment, a circuit that extends the gain versus bias similarity to increase the dynamic range is developed.

In an embodiment, the photodetectors described herein can be easily altered or "adjusted" to provide sensitivity to different spectral bands. The adjustment is provided by the quantum size effect whereby the diameter of the nanoparticle is reduced, and the effective energy gap for forming the quantum dot is increased by the control of synthesis. Another method of adjustment is provided by selecting a material composition, wherein the use of a material having a larger total energy gap generally promotes the implementation of a photodetector having a responsiveness to relatively high photon energy. In an embodiment, photodetectors having different absorption starts can be stacked to form vertical pixels, wherein pixels closer to the optical signal source absorb and induce higher band electromagnetic radiation, and pixels farther away from the optical signal source absorb and sense Lower energy band.

Figure 1 shows a material stack of an embodiment. The material stack is integrated with, but not limited to, a complementary metal oxide semiconductor (CMOS) germanium circuit. Reading a signal converted by a photoconductive photodetector (including an upper surface photodetector including colloidal quantum dots, including PbS) using a CMOS germanium circuit includes integrating an upper surface photoconductive material with a germanium CMOS electronic device Chemical. The structure and composition of the photoconductive photodetector are described in detail below.

Figure 2 shows a cross-section of a stack of materials on a portion of a pixel in an embodiment. This figure depicts a stack of the same materials referenced in Figure 1 on the left and right hand sides or regions. The side center of the device is replaced by a material '7' instead of a material '7' to incorporate a discontinuity. Material '7' can generally be an insulator such as SiO2 or SiOxNy. The embodiment of Figure 2 can be referred to as a portion of one side pixel. In the embodiment, the current flows through the material '2' (interface), the material '3' (adhesion), and the material '4' (photosensitive layer) between the metals '1'. Different portions or regions of the material stack described herein are referred to herein as "materials" or "layers", but are not limited thereto.

Figure 3 shows a cross section of a stack of materials on a pixel of an embodiment. The embodiment of Figure 3 can be referred to as a portion of a vertical pixel. This figure generally describes a stack of the same materials as described above with reference to Figure 1 with materials '1', '2', '3', '4', '5', '6'. An interface material or layer '8' is incorporated or integrated into the top or region of the device. Material '8' is included in one or more members of the material group described herein as material '2'. A metal or contact layer or material '9' is incorporated or integrated into the top or region of one of the devices. The metal or contact layer '9' comprises one or more members of the material group described herein as material '1'. In an embodiment, the material '9' comprises a transparent conductive material such as indium tin oxide, tin oxide, or a thin (substantially non-absorptive to visible light) metal (such as TiN, Al, TaN), or Other metals described by material '1'.

The material "1" is a metal which is located on a substrate (not shown) and which can be a CMOS integrated circuit. During the processing, it can be a 200 mm or 300 mm wafer, that is, a wafer that has not been singulated to form a die. Material "1" refers to a metal present on the top surface of a CMOS integrated circuit wafer that is presented and used for physical, chemical, and electrical connections to its back layer. The metal may comprise: TiN, Ti02, TixNy, Al, An, Pt, Ni, Pd, ITO, Cu, Ru, TiSi, WSi2, and combinations thereof. The material "1" is referred to as a contact, or an electrode, and the behavior of this contact will be discussed here as being affected by a thin layer between the metal and the material "4" (photoconductive quantum dot layer).

The metal can be selected to achieve a particular work function and can affect the formation of ohmic or non-ohmic (e.g., Schottky) contact systems with respect to its proximity. For example, the metal is selected to provide a shallow work function, such as typically between -2.0 eV and -4.5 eV, for example, between -2.0 eV and -4.2 eV.

This metal can reach a surface roughness of less than 5 nm rms.

This metal can be patterned in a critical dimension of 0.18 microns or less. The metal can be patterned such that the pixel-to-pixel, electrode spacing (such as between a pixel intermediate electrode and a grid) does not change by more than 1% of the standard deviation.

The metal may be terminated by a single oxide such as a natural oxide such as TiOxNy in the case of TiN. Typically, such oxides or other materials thereon (such as organic residues, inorganic residues, such as 'polymers', etc.) have consistent and known composition thicknesses.

The metal is a conductive material in which the body of the material constituting the metal may have a resistance of less than 100 micro ohms * cm.

The metal can be processed such that it is not capped with any additional oxides or organics or contaminants on the wafer in all areas where the photosensitive pixels are to be formed.

Before or after the formation of the interfacial layer, the upper surface of the wafer may comprise regions of metal and insulating material (such as insulating oxide) such that the peak-to-valley distance characteristic of the surface is less than 50 nm.

Before the introduction of the photosensitive semiconductor layer, the leakage current flowing between one of the pixel electrodes at the center of the 1.1x1.1 um or 1.4x1.4 um rectangular gate needs less than 0.1 fA at 3V.

The layer or material on material '1' forms an interface or interface layer. Each of the layers forming this interface is described in detail below.

Material "2" is the first portion or first segment of the interface layer and contains the material on the metal. Material '2' may comprise one of the pure surfaces of this metal. The material of this layer may comprise an oxide comprising, by exposure to water, oxygen, or other oxidizing species, typically formed by the presence of exposed metal; or may be formed in a planned manner, such as by exposure to a controlled Environment and exposure to high temperatures, such as rapid thermal processing. Natural oxides include, for example, the following: TiO2 and TiOxNy on TiN; Al2O3 on Al; Au2O3 on Au; PtO or PtO2 on Pt; Ni2O3 on Ni; WO3 on W; PdO on Pd; and oxygen-rich ITO on ITO. This natural oxide can be removed, such as using etching, and replacing it with another layer. For example, a natural oxide such as TiOxNy can be etched (using methods such as argon spray), and then a layer can be deposited thereon, such as a controlled oxide such as TiO2, TiOx, or TiOxNy. The sum of the thickness of the natural oxide and the planned deposited oxide may be between 2 and 20 nm.

A portion of material '2' can be a pair of materials that are substantially transparent to most or all of the wavelengths of visible light. It may have an energy gap greater than 2 eV or greater than 2.5 eV or greater than 3 eV. It can be a doped semiconductor with a large gap. Doping can also be achieved via stoichiometry, such as where x is altered by TiOx below or above material 2 to achieve net doping. The value of x is typically 1.9 to achieve an excess of Ti over stoichiometric TiO2. The value of x can typically be 2.1 to achieve an excess of O over stoichiometric TiO2. TiOx wherein x < -2 can be achieved by exposing stoichiometric TiO2 to a reducing environment. The density of free electrons can be increased by increasing the extent to which the initial stoichiometry of TiO2 is reduced (which corresponds to a larger n-type doping), ie, a greater reduction in TiOx than the value 2 series. x. TiO2 can be doped with nitrogen to improve its free carrier concentration, work function, and electron affinity. TiO2 or TiOx can be doped with B, C, Co, Fe. It can be a slightly n-type material such as a lightly doped TiOx having an equilibrium carrier density of 10^10 cm-3. It may be a moderately doped n-type material, such as TiOx having an equilibrium carrier density of 10^16 cm-3. It can be a more strongly doped n-type material, such as TiOx having an equilibrium carrier density of 10^18 or 10^19 cm-3. Its electron affinity actively and substantially closely corresponds to the work function of such materials. Its work function can substantially closely correspond to the work function of such materials. Its ionization potential can be located at a deeper energy than the ionic potential of the light absorbing layer (the material '4' described herein). It can be treated by an annealing method, a gas phase treatment, or a chemical treatment (such as exposure to organic molecules) to cause a hole in an adjacent semiconductor layer (such as a light absorbing layer (ie, '4' discussed below) A low surface recombination rate is achieved upon contact.

Material '3' may also be present in the interfacial layer and comprise a material that may be placed on or over the first portion of the interfacial layer. The material '3' contains adsorbed organic matter (such as organic molecules) which is introduced by plan or accidentally or via a combination of these, which is located on the metal, in direct contact with the metal, or in direct contact with the metal oxide. . These molecules are discussed in detail here.

The example contains material '2' but lacks material '3'. Such embodiments include materials that are selected without the need for an adhesive layer such as by the material '3'. For example, if the material '2' is combined with a metal such as titanium (such as if the material is '2' and nano TiOx), and if the material is '4' and a crosslinking agent (such as benzoic acid), If one of the functional groups on the formic acid is combined with TiOx), the adhesion between the material '4' and the material '2' can be provided without the explicit inclusion of the material '3'.

In the embodiment, the owner of material '1', material '2', and material '3' may be present. Embodiments include the case where a Schottky contact is unintentionally introduced into a heterojunction via metal '1' and material '4'. Embodiments include a metal in which TiN or TiOxNy forms a metal '1', a layer '2' is a pure end of the metal '1' without substantial formation of a natural oxide, and an adhesive layer (such as hexamethyldioxane) can be Device provided by material '3'.

The owner of the material of the embodiment '1', the material '2' and the material '3' may be present. The embodiment includes the case where one of the heterojunctions with the photosensitive layer '4' is formed by using the oxide of the large energy gap through the material '2'. Embodiments include a semiconductor in which TiN or TiOxNy forms a metal '1', and a layer '2' includes a large gap semiconductor (such as TiOx (which may be structurally doped, impurity doped, or both, or none) And) an adhesive layer (such as hexamethyldioxane) may be provided in the device '3'.

In an embodiment, the material '1' may be aluminum metal, the material '2' may comprise a natural oxide of aluminum, and may comprise a doped conductive oxide (such as doped Al 2 O 3 ), and/or may a semiconductor comprising a large energy gap, such as TiOx (which may be structurally doped, impurity doped, or both, or none), and the material '3' may comprise an adhesive layer (such as Dioxazolidine).

In an embodiment, the material '1' may include aluminum, gallium, indium, tin, lead, antimony, magnesium, calcium, zinc, molybdenum, titanium, vanadium, niobium, chromium, manganese, iron, cobalt, nickel, copper, zirconium, Antimony, palladium, silver, antimony, bismuth, tungsten, antimony, platinum, gold. In the examples, metals for standard CMOS (such as aluminum, tungsten, tantalum, titanium, copper) are preferred.

In an embodiment, the material '2' may include the surface of the metal, and may include aluminum, gallium, indium, tin, lead, antimony, magnesium, calcium, zinc, molybdenum, titanium, vanadium, niobium, chromium, manganese, iron, Cobalt, nickel, copper, zirconium, hafnium, palladium, silver, ruthenium, osmium, tungsten, rhenium, platinum, gold oxides, nitrides, or oxynitrides. In an embodiment, it is preferred to include an oxide, a nitride, or an oxynitride of a metal such as aluminum, tungsten, tantalum, titanium, or copper for standard CMOS.

In an embodiment, material '2' may comprise a plurality of sublayers. In an embodiment, it may comprise a material such as aluminum, gallium, indium, tin, lead, antimony, magnesium, calcium, zinc, molybdenum, titanium, vanadium, niobium, chromium, manganese, iron, cobalt, nickel, copper, zirconium, The sublayer consisting of ruthenium, palladium, silver, iridium, ruthenium, tungsten, rhenium, platinum, and gold. In an embodiment, it is preferred that the layer may comprise a metal for standard CMOS (such as aluminum, tungsten, tantalum, titanium, copper). In an embodiment, the material '2' may comprise aluminum, gallium, indium, tin, lead, antimony, magnesium, calcium, zinc, molybdenum, titanium, vanadium, niobium, chromium, manganese, iron, cobalt, nickel, copper, An additional sublayer of zirconium, hafnium, palladium, silver, ruthenium, osmium, tungsten, rhenium, platinum, gold oxides, nitrides, or oxynitrides. In an embodiment, it is preferred that the additional sublayer comprises an oxide, nitride, or oxynitride of a metal for standard CMOS such as aluminum, tungsten, tantalum, titanium, or copper.

The layer referred to as material '4' refers to a light absorbing layer comprising nanocrystalline or quartz dots. A quantum dot (QD) (described as '1220' in Figure 1) can be a nanostructure, for example, a semiconductor nanostructure that limits the conduction band electrons, valence band holes, or radicals in all three spatial directions. Sub (conductor band electrons and valence banding holes). This limitation may be due to electrostatic potential (eg, by external electrodes, doping, strain, impurities), different semiconductor materials (eg, core-shell nanocrystal systems, which are incorporated in '1221 of Figure 1). Or a semiconductor with another material (for example, by an organic ligand; or by a dielectric substance such as an oxide (such as PbO), a sulfide (such as PbSO3), a sulfate (such as PbSO4) , or SiO2) mounted semiconductor, which is also present in one of the interfaces between '1221' in Figure 1 and is present in the presence of one of the semiconductor surfaces in '1221' of Figure 1, or One or a combination of the majority. A quantum dot exhibits the effect of an individual quantized energy spectrum of an idealized zero-scale system in its absorption spectrum. The wave function corresponding to this individual energy spectrum is substantially spatially localized within the quantum dot, but extends over many of the lattice of the material. In an exemplary embodiment, the QD can have a core of a semiconductor or compound semiconductor material (such as PbS). The ligand can be attached to some or all of the outer surface, or can be removed in certain embodiments. In some embodiments, the cores of adjacent QDs can be fused together to form a continuous film of nanomaterials having nanometer specifications. In other embodiments, the cores can be linked to one another by linker molecules. In some embodiments, the captured state can be found on the outer surface of the nanomaterial. In certain embodiments, the core can be PbS and the capture state can be formed by an oxide such as PbSO3 formed on the outer surface of the core.

A QD layer can have a continuous network of molten QD cores having a composition that is different from the core, such as an oxidized core material (such as PbSO3), or a different type of semiconductor outer surface. The individual QD nuclei of this film are intimately contacted, but continue to exhibit many of the properties of individual quantum dots. For example, a single (unmelted) quantum dot has a characteristically characterized exciton absorption wavelength peak resulting from a quantum effect associated with its size (eg, 1-10 nm). The peak of the exciton absorption wavelength of the molten QD in this film is not significantly shifted from the central absorption wavelength existing before the melting. For example, the central absorption wavelength at the time of melting may vary by about 10% or less. Therefore, the QD within the film maintains its quantum effect, even though it may be an integral part of a giant structure. In certain embodiments, the QD core is linked by a linker molecule as further described below. This allows the power to flow more easily than a QD that has not been continuously melted through the connection. However, the use of linker molecules to form a continuous film of QD instead of melting such nuclei reduces the dark current of certain photoconductor and image sensor embodiments.

In certain embodiments, the QD layer is exceptionally radiation sensitive. This sensitivity is particularly useful for low radiation imaging applications. At the same time, the gain of the device can be dynamically adjusted to saturate the QDPC, i.e., the other photons continue to provide additional useful information that can be identified by the readout electronics. The adjustment of the gain can be conveniently achieved by varying the voltage deviation of a particular device (e.g., a pixel) and thus forming an electric field. Some embodiments of the QD device include a QD layer and a sub-readout integrated circuit that is specifically designed or pre-manufactured. The QD layer is then formed directly on this specially designed or pre-fabricated electronic readout integrated circuit. The QD layer can be additionally patterned to form individual islands. In some embodiments, the QD stack is placed on a circuit that overlaps and contacts at least some of the features of the circuit. In some embodiments, if the QD is stacked with the three-dimensional features of the circuit, the QD layer can conform to these features. In other words, there is a substantially immediate interface between the QD layer and the underlying electronic readout integrated circuit. One or more electrodes of the circuit contact the QD layer and are capable of sustaining protection of information about the QD layer, for example, an electrical signal associated with the amount of radiation on the QD layer, to a readout circuit. The QD layer can be provided in a continuous manner to cover the entire underlying circuitry (such as a readout circuitry) or to form a pattern. If the QD layer is provided in a continuous manner with a fill factor of up to about 100%, this fill factor is reduced when patterned, but some exemplary CMOS inductors using a phosphor diode can still be much larger than the typical 35%. In many embodiments, QD optics are readily fabricated using techniques that can be used in devices commonly used to fabricate conventional CMOS devices. For example, a QD layer can be solution coated onto a pre-fabricated electronic readout circuit using spin coating (which is a standard CMOS method) and optionally further processed by other CMOS compatible techniques. The final QD layer for this device is provided. Because the QD layer does not need to be fabricated in a peculiar or difficult technique, but can alternatively be fabricated using standard CMOS methods, QD optics can be fabricated in high volume and have no significant increase in capital cost (non-material) compared to today's CMOS processing steps. .

The QD material has an absorption cut at about the edge of visible light (such as about 650 nm). The QD material can have an absorption cutoff at longer wavelengths to ensure high absorption throughout the visible light, such as absorption cutoff in the 700-900 nm range.

The QD film can be deposited using conventional spinning methods, ink jet printing methods, Langmuir-Blodgett film deposition, electric spraying, or nanoimprinting. The .QD film can be deposited by dispensing the QD solution onto a wafer at 30 RPM and thereafter in a three-step rotation process.

The spectral position of the absorption peak of the QD solution can be specified at 740 nm, +/- 10 nm. The ratio of the absorption of the QD absorption peak near 740 nm and the valley of the blue slightly to this peak can be specified as 1.2.

The thickness of the quantum dot layer can be specified to be 300 nm. +/- 50 nm. The thickness of the quantum dot layer can be selected to ensure that in the spectral range of 400-640 nm, more than 90% of all light incident on the film is absorbed. The roughness (root mean square value) of the quantum dot film can be specified to be less than 5 nm.

The dark current of 1.1 x 1.1 um pixels at appropriate deviations (such as 3V deviation) may be less than 0.5 fA. Gains at 1.1x1.1um can be greater than 10.

The alkali metal impurities may be present in the quantum dot film at a concentration lower than 5E17 cm-3. Defects larger than 0.16 microns can be less than 20 on a 200mm wafer. The mobility of the flow carrier can exceed 1E-5 cm2/Vs. The loading fraction of the nanocrystals in this film may exceed 30% by volume.

Also included in the material '4' are chemical species such as PbO, PbSO4, PbSO3, polysulfate; and they may also contain physically adsorbed species such as O2, N2, Ar, H2, CO2, H2O, and H2S.

Also incorporated within the material '4' may be a molecule that binds to at least one nanoparticle, or nanocrystals, or the surface of a quantum dot. These may include thiol terminated ligands such as phenylthiol, ethane thiol; carboxylic acid ester terminated molecules such as oleic acid and formic acid; amine terminated ligands such as pyridine , butylamine, octylamine. It may also contain bidentate crosslinkers such as phenyldithiol, ethane dithiol, and butane dithiol. It may also comprise (1) a backbone; (2) specific side groups and/or terminal groups bonded to the surface of the nanoparticle, comprising thiols, amines, carboxylates; and (3) other functional groups, For example, a multidentate molecule that imparts solubility in a solvent that is polar, non-polar, and partially polar.

Material '5' may be included on top of '4', which provides passivation of the underlying material, including the layer '1'-'4' of the material stack and the outer side of the material stack The degree of movement is minimal. This layer can also promote good physical adhesion to the stacked layers, such as the encapsulation layer.

Material '6' refers to a layer that can be included on top of the stack of materials and can be used to minimize the movement of the layers '1'-'4' of the material stack and the outer sides of the stack of materials. Or multiple layers. In a planar cell structure, the quantum dot film layer can be provided with a low-temperature (less than 100oC) PECVD SiO2, SiN, or SiOCN method to provide an optically transparent film suitable for further integration with CFA, and encapsulated to resist oxygen and moisture. diffusion. This film can be specified to have a thickness of 200 nm +/- 10 nm. It can be specified to have a surface roughness of less than 5 nm rms. The optical transmittance can exceed 99%. Adhesion can be provided for the underlying layer. One embodiment has less than 20 particle defects greater than 0.1 um on a 200 mm wafer. An embodiment can have less than 20 pinholes greater than 0.1 um on a 200 mm wafer.

The nature of the interface between the electrical contacts and the photosensitive semiconductor is an important determinant of device stability and performance. For example, regardless of whether the contact is ohmic to Schottky, and whether the contact and the semiconductor are separated by a thin interfacial layer that at least one of {semiconductor and contact} is isolated, stability and performance are important.

The composition of the photoconductive layer - for example, the presence of a surface-capturing state on the semiconductor material constituting the photoconductor - is an important determinant of the performance and stability of the device. In particular, photoconducting materials are generally sensitive to the presence of physically absorbed or chemically absorbed species on the surface of the nanoparticles (possibly from the presence of a gas (such as O2, H2O, CO2)). Care must be taken during processing and a package and/or passivation layer can be used above and/or below the photoconductive layer to avoid fixed photoconductivity failure over time. Further description is made after the interface between the metal and the semiconductor of one embodiment and the package of an embodiment.

Layer '4' can be made from ruthenium (including single crystal ruthenium, polycrystalline ruthenium, nanocrystalline ruthenium, or amorphous ruthenium (including hydrogenated amorphous ruthenium)).

Layer '4' may comprise a non-substantially quantum confinement, and conversely a material that substantially maintains the energy gap of a bulk semiconductor. Examples include crystals or polycrystals or naphthalenes of materials such as germanium, gallium, arsenic, carbon, PbS, PbSe, PbTe, Bi2S3, In2S3, copper-indium-gallium-selenide (or sulfide), SnS, SnSe, SnTe A crystalline or amorphous embodiment of the invention wherein the characteristic dimension of any crystalline or partially crystalline subunit is typically not less than the Bohr exciton radius of the semiconductor material used (the degree of characteristic space of the electron-hole pair).

The interface formation of an embodiment may include the cleaning and termination of the material '1'.

The interface of an embodiment may comprise an oxide formed on material '1' comprising a natural oxide as part of material 7. The thickness of this oxide is an important determinant of device performance. Excessive oxide thickness (e.g., thicknesses in excess of 10-20 nm) provides an excessive contact resistance in series with the photoconductor film, requiring an undesired increase in bias c/o bias current. In an embodiment, the thickness of this native oxide is maintained in the range of less than 5 nm.

The interface of an embodiment may comprise another thin layer as part of the material '2', such as TiO2, which is typically included to improve the work function of the interface with the semiconductor to be placed. This layer may provide sensitivity to a charge carrier in embodiments: for example, TiO2 may be configured to facilitate efficient injection of electrons into the conductive strip of the photoconductive layer when operating a bias voltage, but The same bias voltage is obtained from the valence band of the photoconductive semi-conductive layer with a far lower efficiency. TiO2 can be constructed so that electrons can be efficiently extracted from the conductive strip of the photoconductive semiconducting layer when the bias voltage is operated, but the same bias voltage is used to inject the hole into the photoconductivity with a far lower effect. The semiconducting layer is within the price band.

The interface of an embodiment may be another thin layer that is part of the material '2', such as WH-PPV, which is typically included to flow a charge carrier (such as a hole) while blocking the other (such as , the flow of electronic).

The interface of an embodiment may comprise a thin layer as one of the materials '3', possibly a self-organized molecular monolayer designed to combine one side of the molecule with the underlying layer, and The other terminal, in combination with the semiconductor to be placed thereon, ensures controlled electronic communication and also ensures mechanical stability, for example, good adhesion between the materials constituting the multilayer device.

The layered structure of one embodiment provides efficient charge carrier transfer through an interface. In an embodiment, the layered structure can form substantially ohmic contact with the photoconductive semiconductor layer, providing little or no semiconductor wear near the interface, and providing efficient efficiency of at least one charge carrier (eg, electrons, holes) Injection and extraction. In an embodiment, the layered structure can form a Schottky contact with the photoconductive semiconductor layer to provide an energy barrier to be overcome by the charge carrier to be injected and/or obtained. In embodiments, the layered structure can form a selective contact providing an injection of a charge carrier (eg, electron) that is more efficient than providing another (eg, hole) draw; and/or providing a ratio Another type of charge carrier (e.g., a hole) is more efficient to obtain.

The layered structure of an embodiment provides a work function of the contact surface, wherein the effective work function is determined by the material of the electrode, the material of the interface layer, and the thickness thereof.

The layered structure of one embodiment provides a barrier to inhibit undesired transfer of the carrier, for example, a layer that provides an electron trapping state on the surface of the metal electrode in the case of a p-semiconductor photodetector device.

The layered structure of one embodiment provides a strong bond between the photosensitive semiconductor material and the metal electrode.

The layered structure of one embodiment provides high temperature stability of the interface of the metal electrode-semiconductor material.

The structure and composition of an electronic device having an embodiment of an engineered interface layer includes, without limitation, a metal electrode comprising a conventional material for semiconductor fabrication that is easily oxidized in a selected stoichiometric mixture Or nitriding or both, such as Ti, W, Ta, Hf, Al, Cu, Cr, Ag; or those sensitive to oxidation or nitridation, such as Au, Pt, Rh, Ir, Ru, graphite, Amorphous carbon, graphene, or carbon nanotubes. These metal electrodes can also be formed from alloys, conductive glasses, and various conductive intermetallic alloys. The work function of forming the electrodes can be adjusted by exposure to oxygen, nitrogen, or a mixture of such temperatures at a particular temperature for a specified period of time.

The structure and composition of an electronic device of an embodiment includes an interfacial layer on the surface of the metal contact. The interfacial layer of an embodiment comprises an oxide or intermetallic alloy of the elements of the electrode having a maximum thickness sufficient to maintain the ohmic properties of the contacts, but having a minimum thickness sufficient to produce an electron trapping state. This structure can be produced or generated using PVD (physical vapor deposition), ALD (atomic layer deposition), CVD (chemical vapor deposition), ion clustering, ion beam deposition, ion implantation, annealing, or other film deposition methods. Additionally, such membranes may be formed from aqueous and non-aqueous liquid compositions, which may include electrochemical techniques to form hydroxides, oxides, fluorides, sulfides, sulfates, sulfites, sulfonates of such metals. Salts or complexes of acid salts, phosphates, phosphonates, phosphites, nitrates, nitrites, nitrides, carbonates, carbides, and other types. The average thickness of the interfacial layer may vary from 0.1 nm to 0.2 nm to 10 nm to 50 nm depending on the conductivity of the final interfacial layer and the work function of the metal electrode itself.

Example of an embodiment the interface layer further comprises depositing an oxide on the electrode surface, the oxide of doped TiO2, HfO2, Al203, SiO2, Ta2O5, Zn x Al y O, Zn x Ga y O, ZnIn x Sn y O, and similar p-conductive materials. Again, such materials can be deposited using the methods previously described.

The additional nature of the interfacial layer is determined by the necessity of forming relatively strong chemical bonds (preferably covalent) with the components of the semiconducting photosensitive layer. If none of the photosensitive layer provides chemical bonding to the interface layer, the surface of the interface layer is modified with an organic difunctional molecule, wherein one functional group provides selective bonding to the surface of the interface layer, and second The functional group provides linkage to the ligand or directly to the semiconductor nanocrystal bond. These bonding molecules may be formed on a non-conductive alkane or aryl backbone or may be formed on a conductive backbone comprising aniline, acetylene, or other types of sp2 hybrid carbon. The functional group which is bonded to the surface of the oxidized surface or the interface layer of the electrode includes, without limitation, decane, decane, decazane, primary, secondary or tertiary amine, quinone imine, phosphate, hydrazine , a carboxylic acid ester. The average length of the organic molecules forming the interfacial layer can typically vary from 2 to 16 carbon atoms.

If the metal of the electrode is blunt (eg, An, Pt, Cu, Ag, etc.), the interfacial layer may be formed from a molecule that provides a similar functional group that is directly bonded to the metal surface of one side and the nanocrystal of the other side. . An example is the formation of an Au-S-R-S-NC bond. Furthermore, the thickness and conductivity of the organic interface layer are defined by the desired electronic device properties.

If the conductivity of the interface layer exceeds the allowable limits required for electronic device parameters (for planar electrode elements), the continuous film can be patterned using conventional patterning techniques.

For each electronic device having at least two electrodes, one of the electrodes is made of a metal having a work function, and the other electrode can have a different work function and/or a different conductivity type (electron or hole).

For a vertically structured electronic device, the same manner as above is applied to the bottom electrode, and the interface layer on the top surface is formed by depositing a thin transparent layer of organic molecules or semiconductor materials.

The above molecular system has a polymer having a degree of polymerization of from about 1 to about 10,000.

In forming a device as described herein, generally, the device can be formed to include a consistent and reliable combination of material '1' and material '2', and thereafter controllably form material '3' and light absorbing layer '4 '. For example, an embodiment may pass through a material '1' having a resistance of less than 100 micro ohms*cm and a high conductivity contact between -2eV and -4.5 and a work function between -2eV and -4.2eV. provide. An embodiment may be provided via a material '2' having electrons capable of being injected into a subsequent photosensitive semiconductor layer but blocking the holes from being extracted from the layer. In one embodiment, a controlled thickness of doped substantially transparent oxide, such as n-type TiOx, can be achieved as part of the first portion of material '2'. For example, an embodiment can achieve a TiOx thickness in the range of 2-20, which is controlled within 1-5 nm; and wherein TiOx has a specially selected carrier density of 1 x 1018 cm-3 and has a tight control band spectrum at carrier density. , for example, +/-10%.

The fabrication of the layer stack or structure of the device herein comprises: (1) forming a metal, such as by spraying titanium over a nitrogen atmosphere, causing the formation of TiN; and (2) subsequent processing to cause an interfacial layer (such as, Formation of natural oxides, such as TiOxNy or TiOx) (this subsequent processing can result in a range of possible oxide thicknesses and dopants and carrier supports); (3) via etching, such as sulfuric acid-peroxidation Deionized water etching, or ammonium peroxide etching, or physical etching (argon argon sputtering), or reactive sputtering etching (such as argon and hydrogen), removing the native oxide layer; In an embodiment, the etch completely removes the oxide; the over-etched etch to ensure complete removal is operable; (4) an embodiment deposits a controlled thickness, controlled doping, and controlled surface The final oxide layer, such as TiOx, TiOxNy, or other interfacial layer. A method such as physical vapor deposition (a TiOx source, a TN source, or a DC source of DC splatter, RF splatter included in the presence of a mixture of O2, N2, or the like) can be used to deposit such layers. The method also includes CVD and ALD, wherein a precursor is first deposited on the surface of the wafer and a reaction is carried out at a controlled temperature. In the case where TiOx is to be formed, a precursor can be used.

Fabrication of the stack or structure of layers of the device herein may include: (1) forming a metal, such as by titanium sputtering in a nitrogen atmosphere, causing the formation of TiN; (2) in situ transfer on top of the metal An interface layer is deposited. This may comprise TiOx or TiOxNy. These layers may have a controlled thickness, controlled doping, and an oxide layer that is terminated by a controlled surface, such as TiOx, TiOxNy, or other interfacial layers. A method such as physical vapor deposition (a TiOx source, a TN source, or a DC source of DC splatter, RF splatter included in the presence of a mixture of O2, N2, or the like) can be used to deposit such layers. The method also includes CVD and ALD, wherein a precursor is first deposited on the surface of the wafer and a reaction is carried out at a controlled temperature. In the case where TiOx is to be formed, a chemical precursor can be used.

As noted above, the encapsulating and/or passivating layers can be used above and/or below the photoconductive layer to maintain consistent photoconductive characteristics over time. The embodiments described herein ensure a consistent gas environment within the photoconductive layer (or no substantial amounts of gas present). For example, vacuum, argon, nitrogen, oxygen, hydrogen, carbon dioxide may be included or excluded, in various ratios and to varying degrees. Embodiments may exclude oxygen, H2O, CO2, and may be free of gaseous molecules, or only non-reactive materials such as argon and/or nitrogen. In order to maintain consistent photoconductive characteristics over time, an encapsulation layer may be included for the purpose of avoiding gas exchange between the photoconductive layer and the outer regions of the film. The material for this purpose of an embodiment includes, without limitation, polyxylene; As2S3 or As2Se3; Si3N4, SiO2, and mixtures thereof, ie, SiOxNy; such as TiO2, HfO2, Al2O3, SiO2, Ta2O5, ZnxAlyO , ZnxGayO, ZnInxSny oxide.

The encapsulating material may be provided by a passivation layer, which may be in the form of a substantially monomolecular monolayer. The first layer can be used to protect the encapsulated structure during deposition of the encapsulant: for example, a layer of material such as polyxylene can be deposited using a procedure that does not adversely alter the photo-electric behavior of the photoconductive layer, and Photoconductive layer protection is provided during subsequent encapsulation methods. It may, for example, protect the film from the reaction of oxygen and the bases present during the deposition of oxygen-containing encapsulants (such as SiOx, SiOxNy, etc.).

In an embodiment, the typical thickness of the total encapsulant stack (which may include a plurality of layers) may range from a single monolayer (typically ~nm or slightly sub-nm, eg, 5A) to a typical upper 1 micron. In embodiments, the total thickness of the total encapsulant stack may desirably be 1-2 microns to minimize interference with optical properties of the array.

In an embodiment, at least one of the layers '1', '2', '3', '4', '5' may be used to remove material that can be used with the device (including if the reaction changes device) The material of the photoelectric property) the material of the reaction. Examples of reactive molecules that will enter the device include O2 and H2O and O3. Examples of materials within the device that may have optoelectronic properties that are altered by such reactions include the material '4' NC, the material '3' adhesion, the material '2' interface, and the '1' metal. Examples of the scavenging action include boron nitride, borohydride (including tetrahydroborate), catechin borane, lithium tri-sec-butylborohydride, lithium borohydride, lithium triethylborohydride, and hydroboration. Sodium, and uranium borohydride. Examples of the scavenging action include hydrolyzable alkane.

The device of an embodiment may comprise a strong chemical bond (e.g., covalent) to a component of the semiconductive layer of the semiconductor. Where no component of the photosensitive layer provides chemical bonding with the interface layer, the surface layer of the interface layer is modified with an organic difunctional moiety, wherein a functional group provides selective bonding to the surface of the interface layer, and The second functional group provides a bond to the ligand or directly to the semiconductor nanocrystal. These bonding molecules can be formed on a non-conductive alkane or aryl backbone or can be formed on a conductive backbone comprising aniline, acetylene, or other types of sp2 hybrid carbon. The functional group providing the bond to the oxide may comprise a decane, a decane, a decane, a primary, secondary or tertiary amine, a quinone imine, a phosphate, a hydrazine, a carboxylic acid ester.

The method of fabricating an apparatus of an embodiment can include pre-cleaning the wafer using SCI at 20 ° C for 30 seconds in a clean dry air atmosphere. The method of making the apparatus of one embodiment can be carried out by rinsing in deionized water at 20 ° C for 30 seconds in a clean dry air atmosphere. The method of fabricating an apparatus of an embodiment can include drying the wafer in a specified environment (such as clean dry air, vacuum, nitrogen, argon, or a reducing atmosphere (such as hydrogen), or containing an inert gas (such as , a controlled oxidizing atmosphere of N2 or Ar) and an oxidizing gas (such as O2), baked at a specified temperature (such as 20, 70, 150, or 200 ° C) for a specified time (such as 30 seconds - 24 hours) .

The method of fabricating an apparatus of an embodiment may include specifying maximum and minimum and average latency between other processing methods.

The method of fabricating an apparatus of an embodiment can comprise treating a substrate and a quantum dot film comprising ethane disulfide exposed to acetonitrile at a specified temperature (such as N2) at a specified temperature (such as 25 ° C). The alcohol is given a specified time (such as 20 seconds). The method of fabricating an apparatus of an embodiment can comprise treating a substrate and a quantum dot film comprising hexane disulfide exposed to acetonitrile at a specified temperature (such as N2) at a specified temperature (such as 25 ° C). The alcohol is given a specified time (such as 20 seconds).

The method of fabricating an apparatus of an embodiment may comprise depositing a dielectric capping layer (such as SiO2) at or below a specific temperature (such as 100 ° C), and forming a dielectric seal of a specific thickness at, for example, 100 ° C. Cover.

The method of fabricating an apparatus of an embodiment includes lithography defining a region to be etched, followed by etching a material comprising SiO2.

The method of fabricating an apparatus of an embodiment may comprise depositing a dielectric capping layer (such as SiN) at or below a specific temperature (such as 100 ° C), and forming a dielectric seal of a specific thickness at, for example, 100 ° C. Cover.

The method of fabricating an apparatus of an embodiment includes lithography defining a region to be etched, followed by etching a material comprising SiN.

The method of fabricating an apparatus of an embodiment can include the fabrication of germanium CMOS, including techniques for processing on a 200 nm Si wafer prior to deposition of the quantum dot layer and standard Al/SiO2 materials at 0.11 micron nodes. The CMOS fabrication stream can be completed with a patterned metal contact such as TiN.

The method of fabricating an apparatus of an embodiment can include integrating a Cu/TEOS/SiN HM single corrugated layer on a via layer, followed by selective electroless deposition of the Ni/Au stack.

The method of fabricating an apparatus of an embodiment can include pretreatment of a substrate. Modification of the metal electrode and/or dielectric surface may require improved electrical contact or adhesion between the layers. Instead of pre-cleaning after wet, the wafer can be processed by plasma or by liquid or vapor phase to form an adherent monolayer with controlled barrier thickness and surface state density.

The method of fabricating an apparatus of an embodiment can include depositing a photosensitive film wherein tight control of the surrounding atmosphere is provided to minimize and/or control the impact of oxygen and moisture on film performance. It may include production tools that use a O2 and H2O processing monitor. Standard operating procedures can be provided to ensure minimal, or controlled and consistent materials (such as quantum dots and their layers) exposed to air, contained during chemical storage, and fluid transferred from the storage container to the processing tool tank. The manufacturing process is compatible with chloroform and other solvents.

The method of fabricating an apparatus of an embodiment can include stabilizing the quantum dot layer. These may include chemical post treatments of dithiol dilute solutions used in acetonitrile.

Due to the high sensitivity of QF to the surrounding oxygen and moisture, the waiting time between QF deposition and post-treatment needs to be minimal and under the N2 layer. The same conditions apply to the waiting time between post-treatment B and dielectric cap deposition.

The method of fabricating an apparatus of an embodiment can include a seal of the QF film to protect against diffusion of oxygen and moisture during the life of the device. Low temperature deposition of the SiO2/SiN stack can be used. These methods need to be carried out at a substrate temperature below 100 ° C and at atmospheric pressure or at as high a pressure as possible. Other methods may include a low temperature spin-on glass process or an ultra-thin metal film that does not affect the optical transmission of the capping layer.

The method control of the apparatus of an embodiment can include feed wafer inspection prior to quantum dot deposition. The detection step of an embodiment comprises: a) detecting defect density, such as using bright field detection; b) metal electrode work function detection, such as using ultraviolet photoelectron spectroscopy (UPS) (UPS method processing control program can be applied to the overlay layer) Processing the monitoring wafer); c) Leakage current and dielectric voltage are destroyed on the TLM (Test Pixel Array) structure. The photovoltaic response and film properties of the device can be implemented as part of a process control.

In an embodiment, the material '4' may comprise a material having an energy gap and providing absorption of light in the wavelength range of interest. In an embodiment, the photosensitive layer may comprise a material such as Si, PbS, PbSe, CdS, CdSe, GaAs, InP, InAs, PbTe, CdTe, Ge, In2S3, Bi2S3, and the like. In an embodiment, the photosensitive layer may comprise a strong light absorbing material such as porphyrin. In embodiments, the photosensitive layer may comprise a passivating organic ligand such as ethanethiol, ethane dithiol, benzene mercaptan, benzene dithiol, diphenyl dithiol, pyridine, butylamine.

In an embodiment, the photodetector of an embodiment comprises a photosensitive device that controls the flow of at least one charge carrier using a photosensitive energy barrier.

In an embodiment, the photodetector can exhibit a gain, wherein the ratio of the number of additional charge cells per second to the number of photons per second impacted on a device can exceed 1, for example, a value in the range of about 2-60.

In an embodiment, the photodetector can exhibit a high normalized response, ie, a high ratio of photocurrent to dark current, even at low light levels. For example, when 150 nW/cm2 of visible light impinges on the photodetector, the ratio of photocurrent to illuminating current can exceed 20. In general, this value needs to be as high as possible (while complying with other regulations, such as on lag and dark current uniformity and photo response uniformity). Values up to 100 and higher are possible for a normalized response of 150 nW/cm2.

In an embodiment, the photodetector can exhibit a fast time response, and the photocurrent (including the following intense illumination, such as 1 uW/cm 2 and greater on the pixel) stays close to the dark current value in less than 1 second ( For example, the dark current is the least significant bit). Ideally, the photocurrent is at this value during an exposure period (which may be 1/15 s, 1/30 s, 1/200 s, 1/1000 s, or the like).

In an embodiment, the current-voltage characteristic in the dark may exhibit a monotonically increasing function relationship between zero and a first voltage (referred to as a saturation voltage). This range can be referred to as the trigger phase. The current-voltage may exhibit a monotonically increasing function having a lower average slope than zero during the first voltage range between the first voltage and the second larger voltage (referred to as the punch-through voltage). This first to second voltage range may be referred to as a saturation range. At voltages greater than the second (or punch-through) voltage, the current-voltage relationship may exhibit a slope that increases relative to the first voltage to the second voltage range. This maximum voltage range can be referred to as the post-punching range.

In an embodiment, the gain may be at a time when the charge carrier (eg, electrons) is flowing through the device under deviation (ie, between the two contacts (such as the material '1' and the right material on the left side of FIG. 2' When the time between 1's operation, or the time between the material '1' and the material '9' in Figure 3) exceeds the average lifetime of the charge carriers, the contacts of the injected charge carriers (eg, electrons) are also avoided. Other types of charge carriers (which may be referred to as hindered carriers (eg, holes)), and when provided at the interface between the contacts of the flow charge carrier (eg, electrons) and the semiconductor film, provide a hindered carrier ( For example, holes are achieved when the surface recombination rate is low. This interface is based on material '2' and material '3' in Figure 1, material '2' and material '3' in Figure 2, and material '7' and material '3' in Figure 2, and Material '2', material '3', material '5' and material '8' are implemented.

More specifically, the gain can be achieved when the flow of charge carriers (e.g., electrons) through the device exceeds the average lifetime of the charge carriers. Quantitatively, the basic transport factor (α-t) is also considered to be less than but close to one. This can be achieved when a small amount of carrier for the flow carrier has a diffusion length that exceeds the separation between the interface layers.

Moreover, the gain can be achieved by injecting a contact of a flowing charge carrier (eg, electron) under bias and also avoiding other types of charge carriers (which can be referred to as a resistive carrier (eg, a hole)). Quantitatively, the emitter injection efficiency (γ) is considered to be less than but close to one. This can be achieved by using an interface layer that injects contacts of the flow carrier that is close to resisting other types of charge carriers. This can be substantially calibrated by the work function of the metal contact from the energy system and the metal contact close to it from one of the band spectra (such as the conductive strip); and the band spectrum of the energy system and the semiconductor that blocks the charge carrier This interface layer is achieved by a large energy gap material that is not calibrated.

Moreover, the gain can be achieved when the interface between the contact of the flowing charge carrier (e.g., electron) and the semiconductor film under bias provides a low surface recombination rate of the resistive carrier (e.g., hole). Quantitatively, the recombinant factor can be considered to be less than but close to one. This may be within a small amount of carrier lifetime of the flow carrier (eg, electrons), only a small fraction of the hindered carrier (eg, a hole) between the contacts providing the flow charge carrier (eg, electrons) and the semiconductor film. Reorganization near the interface. This may require the surface recombination rate of the hindered carrier to be less than 0.1 cm/s, for example, 0.01 cm/s or less.

Referring to Fig. 2, the embodiment may include a method and structure for reducing the dark current passing between the leftmost material '1' and the rightmost material '1'. Embodiments may include removing the conductive portion of the portion of material '3' between the leftmost material '1' and the rightmost material '1'. Embodiments may include the removal of conductivity such as metal oxides, metal hydroxides, organic contamination, polymers, and conductive oxides between the leftmost material '1' and the rightmost material '1'. Part. Referring to Fig. 2, the embodiment may include an interface between the modified material '7' and the material '4' to control the rate of recombination at this interface, the trapped charge, adhesion, or a number of such properties.

Referring to Figure 1, an embodiment includes controlling surface states such as those present at interface layers '2' and '3'. Embodiments include impinging a metal (such as Tin of material '1') or a metal oxyhydride (such as TiOx of material '2') with hydrazine or other species or using argon sputtering to control or improve the rate of recombination on the surface . Embodiments can include reducing the surface recombination rate of a charge carrier to less than 0.1 cm/s or at least 0.01 cm/2 at this interface.

Embodiments include small pixels implemented at a pixel pitch of 0.9 um on each side. Embodiments include the use of narrow vias (such as 0.15 um). Embodiments include the use of 14 um metal to metal spacing.

Embodiments described herein include an optically sensitive device comprising: a first contact and a second contact; each having a work function; an optically sensitive first contact and the second contact a material, the optically sensitive material comprising a p-type semiconductor, and the optically sensitive material has a work function; the circuit is configured to apply a bias voltage between the first contact and the second contact; the optically sensitive material The number of work functions is at least 0.4 eV greater than the number of work functions of the first contact, and is also at least 0.4 eV greater than the number of work functions of the second contact; the optically sensitive material has a greater than when the bias voltage is applied to The electronic lifetime of the electronic running time from the first contact to the second contact between a contact and the second contact; the first contact provides electron injection and blocking of the hole; the first contact The interface between optically sensitive materials provides a surface recombination rate of less than 1 cm/s.

Embodiments described herein include an optically sensitive device comprising a first contact; an n-type semiconductor; an optically sensitive material comprising a p-type semiconductor; a second contact; an optically sensitive material And the second contacts each have a work function that is shallower than 4.5 ev; the circuit is configured to apply a bias voltage between the first contact and the second contact; the optically sensitive material has a greater than when the bias voltage is applied to The electronic lifetime of the electronic running time from the first contact to the second contact between a contact and the second contact; the first contact provides electron injection and blocking of the hole; the first contact The interface between optically sensitive materials provides a surface recombination rate of less than 1 cm/s.

The embodiment described herein includes a photodetector comprising: a first contact and a second contact, each having a work function; and an optical sensitivity between the first contact and the second contact The material, the optically sensitive material comprises a p-type semiconductor, and the optically sensitive material has a work function; the circuit is configured to apply a bias voltage between the first contact and the second contact; the work of the optically sensitive material The number of functions is at least 0.4 eV greater than the number of work functions of the first contact and is at least 0.4 eV greater than the number of work functions of the second contact; the current is configured for the first contact and the second contact A bias voltage is applied therebetween; and the optically sensitive material is configured to provide a responsivity of at least 0.8 A/W when a bias voltage is applied to the first contact and the second contact.

The first contact of the photodetector of an embodiment is an injection contact, and the second contact is a pull contact.

The injection contact of the photodetector of an embodiment is constructed to inject a flowing current into the optically sensitive material with greater efficiency than the injection contact takes a captured carrier from the optically sensitive material.

The injection contact of the photodetector of an embodiment is constructed to obtain a flow carrier from the optically sensitive material with greater efficiency than injection of the captured carrier into the optically sensitive material.

The optically sensitive material of the photodetector of an embodiment is a p-type semiconductor material.

The first contact of the photodetector of an embodiment comprises a metal, and wherein the second second contact comprises a metal.

The bias voltage of the photodetector of an embodiment is in the range of about -0.1 volts to -2.8 volts, and the flow carrier is electrons.

The optically sensitive material of the photodetector of an embodiment comprises nanoparticle selected from the group consisting of PbS, PbSe, PbTe, CdS, CdSe, CdTe, Si, Ge, or C.

Each of the nanoparticles of the photodetector of an embodiment comprises an oxide on the surface of the nanoparticle.

The optically sensitive layer of the photodetector of an embodiment comprises a material selected from the group consisting of PbSO4, PbO, PbSeO4, PbTeO4, SiOxNy, In2O3, sulfur, sulfate, yttrium, carbon, and carbonate.

The nanoparticles of the photodetector of one embodiment are interconnected.

The injection contact and the pull contact of the photodetector of an embodiment each comprise a material selected from the group consisting of Al, Ag, In, Mg, Ca, Li, Cu, Ni, NiS, TiN, or TaN.

The optically sensitive layer of the photodetector of an embodiment has a size in the range of 100 to 3000 nm perpendicular to the incident direction of the light.

The first carrier type of the photodetector of an embodiment is the primary in the dark, and the second carrier type is the primary under illumination.

The first carrier type of the photodetector of an embodiment is a hole, and the second carrier type is an electron.

The first contact and the second contact of the photodetector of an embodiment comprise a metal of a shallow work function.

The first contact and the second contact of the photodetector of an embodiment each have a lighter work function that is shallower than 4.5 eV.

The distance between the first contact and the second contact of the photodetector of an embodiment is in the range of 200 nm to 2 um.

The flow carrier of the photodetector of an embodiment has a mobility of at least 1E-5 cm2/Vs.

The p-type semiconductor material of the photodetector of an embodiment is a doped p-type material.

The bias voltage of the photodetector of an embodiment is in the range of about +0.1 volts to +2.8 volts, and the flow carrier is a hole.

The injection contact and the pull contact of the photodetector of an embodiment each comprise a material selected from the group consisting of An, Pt, Pd, Cu, Ni, NiS, TiN, and TaN.

The first carrier type of the photodetector of one embodiment is the primary of the dark, and the second carrier type of the photodetector of an embodiment is the primary of illumination.

In the first carrier type of the photodetector of an embodiment, the second carrier type is a hole.

The first and second contacts of the photodetector of an embodiment comprise a metal of deep work function.

The first contact and the second contact of the photodetector of an embodiment each have a deeper work function than 4.5 ev.

The photodetector n-type semiconductor material of an embodiment is a doped n-type material.

The optically sensitive material of the photodetector of an embodiment has a work function that is at least 0.3 ev deeper than the work function of the first contact and the second contact.

The first contact and the second contact of the photodetector of an embodiment each comprise a group selected from the group consisting of Al, Ag, In, Mg, Ca, Li, Cu, Ni, NiS, TiN, TaN, n-type polyfluorene And materials of the group consisting of n-type amorphous ruthenium.

Embodiments described herein include a photodetector comprising: a first contact and a second contact; an optically sensitive material between the first contact and the second contact, the optically sensitive material comprising An n-type semiconductor; each of the first contact and the second contact has a deeper work function than 4.5 ev; the circuit is configured to apply a bias voltage between the first contact and the second contact; and is optically sensitive The material is configured to provide a photoconductive gain and a responsivity of at least 0.4 A/W when a bias voltage is applied between the first contact and the second contact.

The optically sensitive material of the photodetector of an embodiment has a work function that is at least 0.3 ev shallower than the work function of the first contact and the second contact.

The first contact and the second contact of the photodetector of an embodiment each comprise a selected from the group consisting of Au, Pt, Pd, Cu, Ni, NiS, TiN, TaN, p-type polyfluorene, and p-type non- The material of the group composed of crystallization enthalpy.

The embodiment described herein comprises a photovoltaic crystal comprising: a first contact and a second contact; an optically sensitive material between the first contact and the second contact, the optically sensitive material comprising a n a type semiconductor; each of the first contact and the second contact has a Schottky contact or a deeper work function than 4.5 ev; the circuit is configured to apply a bias voltage between the first contact and the second contact; And the optically sensitive material has a cavity life greater than a hole running time from the first contact to the second contact when a bias voltage is applied between the first contact and the second contact.

The flow carrier of the photodetector of an embodiment is a hole and the captured carrier is electrons.

The embodiment described herein includes a photovoltaic crystal comprising: a first contact and a second contact; an optically sensitive material between the first contact and the second contact, the optically sensitive material comprising a p-type semiconductor; each of the first contact and the second contact has a Schottky contact or a lighter function than 4.5 ev; the circuit is configured to apply a bias between the first contact and the second contact a voltage; and when the bias voltage is applied between the first contact and the second contact, the optically sensitive material has an electron lifetime; wherein the optical mobility of the optically sensitive material, the first contact and the second contact The distance between the electrodes and the bias voltage are selected such that when the bias voltage is applied between the first contact and the second contact, the electronic runtime from the first contact to the second contact is less than the electron lifetime.

The flow charge of the photodetector of an embodiment is electrons, and the captured carrier is a hole.

The embodiment described herein includes a photovoltaic crystal comprising: a first contact and a second contact; an optically sensitive material between the first contact and the second contact, the optically sensitive material comprising An n-type semiconductor; each of the first contact and the second contact has a Schottky contact or a deeper work function than 4.5 ev; the circuit is configured to apply a bias voltage between the first contact and the second contact The optically sensitive material has a cavity life when a bias voltage is applied between the first contact and the second contact; wherein the hole mobility of the optically sensitive material, between the first contact and the second contact The distance, and the bias voltage are selected such that when a bias voltage is applied between the first contact and the second contact, the hole travel time from the first contact to the second contact is less than the life of the hole.

The flow carrier of the photodetector of an embodiment is a hole and the captured carrier is electrons.

The photodetector of an embodiment comprises a p-type semiconductor comprising p-doped germanium.

The photodetector of an embodiment comprises a p-type semiconductor comprising GaAs.

The photodetector of an embodiment comprises a p-type semiconductor comprising quantum dots/nanocrystals.

The photodetector of an embodiment comprises a p-type semiconductor comprising a network of interconnected nanocrystals.

The photodetector of an embodiment comprises a p-type semiconductor comprising nanocrystals and binder molecules.

The photodetector of an embodiment comprises a p-type semiconductor comprising a compound semiconductor.

The photodetector of an embodiment comprises a p-type semiconductor comprising PbS, PbS with PBSO ₃ .

Embodiments described herein include an optically sensitive device comprising: a first contact and a second contact, each having a work function; and an optic between the first contact and the second contact a sensitive material; the optically sensitive material comprises a p-type semiconductor, and the optically sensitive material has a work function; the circuit is configured to apply a bias voltage between the first contact and the second contact; the optically sensitive material The number of work functions is at least 0.4 eV greater than the number of work functions of the first contact; and is at least 0.4 eV greater than the number of work functions of the second contact; the optically sensitive material has a greater than when the bias voltage is applied to the first The electronic lifetime of the electronic operating time from the first contact to the second contact between a contact and the second contact; the first contact provides electron injection and blocking of the hole; and the first contact The interface with the optically sensitive material provides a surface recombination rate of less than 1 cm/s.

The work functions of the first and second contacts of the device of one embodiment are each shallower than 4.5 ev.

The bias voltage of the device of one embodiment is in the range of about -0.1 volts to -2.8 volts.

The optically sensitive material of the device of an embodiment comprises a plurality of nanoparticles, wherein each nanoparticle has an oxide on the surface of the individual nanoparticle.

The optically sensitive material of the device of an embodiment comprises nanoparticles selected from the group consisting of PbS, PbSe, PbTe, CdS, CdSe, CdTe, Si, Ge, or C.

The optically sensitive layer of the device of one embodiment comprises a material selected from the group consisting of PbSO4, PbO, PbSe04, PbTeO4, SiOxNy, In2O3, sulfur, sulfate, yttrium, carbon, and carbonate.

The optically sensitive material of the device of one embodiment comprises a plurality of interconnected nanoparticles.

The first contact and the second contact of the device of an embodiment each comprise a material selected from the group consisting of Al, Ag, In, Mg, Ca, Li, Cu, Ni, NiS, TiN, or TaN.

The first contact and the second contact of the device of an embodiment are spaced apart by a distance in the range of 200 nm to 2 um, and the electron mobility within the optically sensitive material is at least 1E-5 cm2/Vs.

The optically sensitive material of the device of an embodiment is configured to provide a responsivity of at least .8 A/W when a bias voltage is applied between the first contact and the second contact.

Embodiments described herein include an optically sensitive device comprising: a first contact; an n-type semiconductor; an optically sensitive material comprising a p-type semiconductor; a second contact; optical sensitivity The material and the second contact each have a lighter work function than 4.5 ev; the circuit is configured to apply a bias voltage between the first contact and the second contact; the optically sensitive material has a greater than the bias voltage The electronic lifetime of the electronic runtime from the first contact to the second contact when applied between the first contact and the second contact; the first contact provides electron injection and blocking of the hole; and first The interface between the contacts and the optically sensitive material provides a surface recombination rate of less than 1 cm/s.

The n-type semiconductor of the device of one embodiment comprises a selected from the group consisting of TiO2, chemically reduced TiO2, oxidized TiO2, CdTe, CdS, CdSe, Si, or selected from the group consisting of PbS, PbSe, PbTe, CdS, CdSe, CdTe, Si The material of the group consisting of nanoparticles of the group consisting of Ge, or C.

The bias voltage of the device of one embodiment is in the range of about -0.1 volts to -2.8 volts.

The optically sensitive material of the device of an embodiment comprises a plurality of nanoparticles, wherein each nanoparticle has an oxide on the surface of the individual nanoparticle.

The optically sensitive material of the device of an embodiment comprises nanoparticles selected from the group consisting of PbS, PbSe, PbTe, CdS, CdSe, CdTe, Si, Ge, or C.

The optically sensitive material of the device of one embodiment comprises a plurality of interconnected nanoparticles.

The first contact and the second contact of the apparatus of one embodiment are separated by a distance ranging from 200 nm to 2 um.

The embodiment described herein includes a photodetector comprising: a first contact and a second contact, each having a work function; and an optical sensitivity between the first contact and the second contact The material, the optically sensitive material comprises a p-type semiconductor, and the optically sensitive material has a work function; the circuit is configured to apply a bias voltage between the first contact and the second contact; the work of the optically sensitive material The number of functions is at least 0.4 eV greater than the number of work functions of the first contact and is at least 0.4 eV greater than the number of work functions of the second contact; the circuit is constructed for the first contact and the second contact A bias voltage is applied therebetween; and the optically sensitive material is configured to provide a responsivity of at least 0.8 A/W when a bias voltage is applied between the first contact and the second contact.

The work functions of the first and second contacts of the photodetector of an embodiment are each shallower than 4.5 ev.

The bias voltage of the photodetector of an embodiment is in the range of about -0.1 volts to -2.8 volts.

The optically sensitive material of the photodetector of an embodiment comprises nanoparticle selected from the group consisting of PbS, PbSe, PbTe, CdS, CdSe, CdTe, Si, Ge, or C.

The optically sensitive layer of the photodetector of an embodiment comprises a material selected from the group consisting of PbSO4, PbO, PbSeO4, PbTeO4, SiOxNy, In2O3, sulfur, sulfate, yttrium, carbon, and carbonate.

The first contact and the second contact of the photodetector of an embodiment each comprise a material selected from the group consisting of Al, Ag, In, Mg, Ca, Li, Cu, Ni, NiS, TiN, or TaN .

The first and second contacts of the photodetector of an embodiment are separated by a distance in the range of 200 nm to 2 um, and the electron mobility within the optically sensitive material is at least 1E-5 cm2/Vs.

Unless otherwise expressly required by this disclosure, the term "comprising" is to be interpreted as meaning contrary to the exclusion or exhaustive meaning in the full description and the scope of the patent application; that is, "unrestricted inclusion" meaning. The use of the singular or plural plural also includes the plural or singular. In addition, the words "herein", "under", "above", "below" and the like are used in this application to refer to the entire application and do not refer to any particulars of this application. Part. When the word "or" is used to mean the listing of two or more items, this word includes all of the following explanations of the word: any of the items listed in this list, the owner of the item in the list And any combination of the items listed here.

The above description of the embodiments is not intended to be exhaustive or to limit such systems or methods to the precise forms disclosed. While the embodiments of the present invention and the examples of the embodiments have been described herein by way of example, it will be appreciated by those skilled in the art that various equivalent modifications are possible within the scope of the systems and methods. The teachings of the embodiments provided herein may be applied to other systems and methods, and not only to the systems and methods described above.

The elements and acts of the various embodiments described above can be combined to provide further embodiments. These and other changes can be made to the embodiments based on the detailed description above.

1,2,3,4,5,6,7,8,9. . . material

1220. . . Quantum dot

1221. . . shell

Figure 1 shows a material stack of one embodiment.

Figure 2 is a cross-sectional view showing a stack of materials on a portion of a pixel of an embodiment.

Figure 3 is a cross-sectional view showing a stack of materials on a pixel of an embodiment.

1,2,3,4,5,6. . . material

1220. . . Quantum dot

1221. . . shell

Claims (25)

An optically sensitive device comprising: a first contact and a second contact, each having a work function; an optically sensitive material between the first contact and the second contact, the optical The sensitive material comprises a p-type semiconductor, and the optically sensitive material has a work function; and the circuit is configured to apply a bias voltage between the first contact and the second contact; the optically sensitive material The number of work functions is at least 0.4 eV greater than the number of work functions of the first contact, and is also at least 0.4 eV greater than the number of work functions of the second contact; the optically sensitive material has a ratio An electronic lifetime of greater electron travel time from the first contact to the second contact when the bias voltage is applied to the first contact and the second contact; the first contact provides injection of electrons and The extraction of the hole is blocked; and the interface between the first contact and the optically sensitive material provides a surface recombination rate of less than 1 cm/s. The device of claim 1, wherein the work function of the first contact and the second contact is each shallower than 4.5 eV. The device of claim 1, wherein the bias voltage is in the range of -0.1 volts to -2.8 volts. The apparatus of claim 1, wherein the optically sensitive material comprises a plurality of nanoparticles, wherein each of the nanoparticles has an oxide on a surface of the individual nanoparticle . The device of claim 1, wherein the optically sensitive material comprises a material selected from the group consisting of PbS, PbSe, PbTe, CdS, CdSe, CdTe, Si, Nano particles of the group consisting of Ge, or C. The device of claim 5, wherein the optically sensitive layer further comprises one selected from the group consisting of PbSO ₄ , PbO, PbSeO ₄ , PbTeO ₄ , bismuth oxynitride, In ₂ O ₃ , sulfur, sulfate, and arsenic. A material of the group consisting of carbon and carbonate. The device of claim 1, wherein the optically sensitive material comprises a plurality of interconnected nanoparticles. The device of claim 1, wherein the first contact and the second contact each comprise an element selected from the group consisting of Al, Ag, In, Mg, Ca, Li, Cu, Ni, NiS, TiN, TaN, TiO ₂ , ITO, Ru, TiSi, WSi ₂ , B doped TiO ₂ , C doped TiO ₂ , Co doped TiO ₂ , Fe doped TiO ₂ , doped with Nd A material of a group consisting of TiO ₂ and N-doped TiO ₂ . The device of claim 1, wherein the first contact and the second contact are separated by a distance ranging from 200 nm to 2 μm, and the optical mobility of the optically sensitive material is at least 1E-5 cm ² / Vs. The device of claim 1, wherein the optically sensitive material is configured to provide a responsivity of at least 0.8 A/W when the bias voltage is applied between the first contact and the second contact. . An optically sensitive device comprising: a first contact; an n-type semiconductor; an optically sensitive material comprising a p-type semiconductor; a second contact; The number of work functions of the optically sensitive material is at least 0.4 eV greater than the number of work functions of the first contact and is at least 0.4 eV greater than the number of work functions of the second contact; The sensitive material has an electron lifetime greater than an electron running time from the first contact to the second contact when a bias voltage is applied between the first contact and the second contact; the n-type semiconductor Electron injection and blocking of the hole are provided; and the interface between the n-type semiconductor and the optically sensitive material provides a surface recombination rate of less than 1 cm/s. The device of claim 11, wherein the n-type semiconductor comprises a selected from the group consisting of TiO ₂ , chemically reduced TiO ₂ , oxidized TiO ₂ , CdTe, CdS, CdSe, Si, or selected from PbS, A material consisting of a group of nanoparticles of PbSe, PbTe, CdS, CdSe, CdTe, Si, Ge, or C. The device of claim 11, wherein the bias voltage is in the range of -0.1 volts to -2.8 volts. The apparatus of claim 11, wherein the optically sensitive material comprises a plurality of nanoparticles, wherein each of the nanoparticles has an oxide on a surface of the individual nanoparticle . The device of claim 11, wherein the optically sensitive material comprises nanoparticle selected from the group consisting of PbS, PbSe, PbTe, CdS, CdSe, CdTe, Si, Ge, or C. The device of claim 11, wherein the optically sensitive material comprises a plurality of interconnected nanoparticles. The device of claim 11, wherein the first contact and the second contact are separated by a distance ranging from 200 nm to 2 μm. The device of claim 11, wherein the first contact and the second contact each comprise an element selected from the group consisting of Al, Ag, In, Mg, Ca, Li, Cu, Ni, NiS, TiN, TaN, TiO ₂ , ITO, Ru, TiSi, WSi ₂ , B doped TiO ₂ , C doped TiO ₂ , Co doped TiO ₂ , Fe doped TiO ₂ , doped with Nd A material of a group consisting of TiO ₂ and N-doped TiO ₂ . A photodetector comprising: a first contact and a second contact, each having a work function; an optically sensitive material between the first contact and the second contact, the optical sensitivity The material comprises a p-type semiconductor, and the optically sensitive material has a work function; and the circuit is configured to apply a bias voltage between the first contact and the second contact; the optically sensitive material The number of work functions is at least 0.4 eV greater than the number of work functions of the first contact and is at least 0.4 eV greater than the number of work functions of the second contact; and the optically sensitive material is constructed A responsivity of at least 0.8 A/W is provided when the bias voltage is applied between the first contact and the second contact. The photodetector of claim 19, wherein the work function of the first contact and the second contact is each lighter than 4.5 eV. The photodetector of claim 19, wherein the bias voltage is in the range of -0.1 volts to -2.8 volts. The photodetector of claim 19, wherein the optically sensitive material comprises nanoparticle selected from the group consisting of PbS, PbSe, PbTe, CdS, CdSe, CdTe, Si, Ge, or C. The photodetector of claim 22, wherein the optically sensitive layer further comprises one selected from the group consisting of PbSO ₄ , PbO, PbSeO ₄ , PbTeO ₄ , bismuth oxynitride, In ₂ O ₃ , sulfur, sulfate, and sub Materials of the group consisting of bismuth, carbon, and carbonate. The photodetector of claim 19, wherein the first contact and the second contact each comprise an element selected from the group consisting of Al, Ag, In, Mg, Ca, Li, Cu, Ni, NiS, TiN, TaN, TiO ₂ , ITO, Ru, TiSi, WSi ₂ , B doped TiO ₂ , C doped TiO ₂ , Co doped TiO ₂ , F doped TiO ₂ , Nd A material of a group consisting of doped TiO ₂ and N-doped TiO ₂ . The photodetector of claim 19, wherein the first contact and the second contact are separated by a distance ranging from 200 nm to 2 μm, and the optical mobility of the optically sensitive material is at least 1E-5 cm. ² /Vs.