US3666450A - Photoconductive ternary alloy of cadmium,selenium and mercury - Google Patents

Photoconductive ternary alloy of cadmium,selenium and mercury Download PDF

Info

Publication number
US3666450A
US3666450A US18248A US3666450DA US3666450A US 3666450 A US3666450 A US 3666450A US 18248 A US18248 A US 18248A US 3666450D A US3666450D A US 3666450DA US 3666450 A US3666450 A US 3666450A
Authority
US
United States
Prior art keywords
photoconductive
mercury
alloy
cadmium
selenium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US18248A
Other languages
English (en)
Inventor
Tadao Nakamura
Tadao Kohnashi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Application granted granted Critical
Publication of US3666450A publication Critical patent/US3666450A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C28/00—Alloys based on a metal not provided for in groups C22C5/00 - C22C27/00
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/02—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working in inert or controlled atmosphere or vacuum
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S420/00—Alloys or metallic compositions
    • Y10S420/903—Semiconductive

Definitions

  • a novel photoconductive crystalline ternary alloy prepared from a host material containing cadmium, selenium and mercury and doped with an activator and coactivator, said host material being fired at least once until the crystallization thereof is complete and a photosensitivity peaking up in the infrared spectral range is attained.
  • the activator is selected from any of Ib group elements consisting of copper and silver
  • the coactivator is selected from an of VIIb group elements consisting of chlorine, bromine and iodine or from any of I IIb group elements consisting of aluminum, gallium and indium.
  • the present invention relates to a novel photoconductive crystalline ternary alloy containing cadmium, selenium and mercury and having photosensitivity which peaks up in the infrared spectral range.
  • the invention includes improved methods for preparing the photoconductive alloy.
  • a photoconductive device is one which displays a reduced resistance to an electric current flow when irradiated, as for example, vw'th light.
  • a photoconductive device comprises a body of photoconductive material and a pair of electrodes attached thereto. With a voltage applied to the electrodes, the device passes an increased amount of electric current in the event of an increase in the intensity of light irradiating the device.
  • the photoconductive alloy of the invention as applicable for such device is based on the discovery made by us that the ternary alloy containing cadmium, selenium and mercury behaves as a semiconductor of N type. This alloy exhibits photoconductivity particularly to irradiating light of the infrared range, when doped with suitable impurities.
  • the semiconductor of the invention is composed substantially of ternary alloy doped with lb and VIIb group elements as impurities, which alloy is expressed, in the general form, Cd Hg Se, where x l. With respect to the doped impurities, the Ib group element acts as an activator while the VIIb group element as a coactivator. IIIb group elements may also be employed in place of the VIIb group elements.
  • x may assume any value so long as it lies in the range between zero and one.
  • Experiments thus far conducted have revealed that as x approaches zero the spectral sensitivity of the alloy shifts toward the longer wavelength in the infrared range.
  • Photoconductive crystalline ternary alloy according to the invention is prepared by firing the host material containing cadmium, selenium and mercury and by doping the host material with vIb group elements including copper and silver as an activator and VIIb or IIIb group elements including chlorine, bromine and iodine, or aluminum, gallium and indium, respectively, as a coactivator.
  • the photoconductive alloy of the invention is characterized in that the alloy exhibits its maximum photosensitivity in the infrared spectral range.
  • a photoconductive device according to the invention comprises a mass of the photoconductive alloy of the invention with or without a binder and a pair of electrodes attached thereto.
  • FIG. 1 is a perspective view showing a photoconductive device according to the invention.
  • FIG. 2 is a series of characteristic curves showing the spectral sensitivities of some typical photoconductive alloys of the invention.
  • the host material containing cadmium, selenium and mercury each in the form of elementary substance is fired twice at two different temperatures. More specifically, a starting or host mixture contains predetermined amounts of pure cadmium, selenium and mercury. This starting mixture is fired preferably at 700 to 800 C. under the pressure of to atm. in an inert gas atmosphere until a homogeneous a1- loy is obtained therefrom. The product obtained after the first firing is re-fired at 1,100 to l,200 C. under the pressure of 70 to 100 atm. in an inert gas atmosphere until the crystallization of the starting material is complete. In this instance, the introduction of the impurities can be performed in two different fashions.
  • the impurities to be added are previously mixed with the starting material and therefore the succeeding firing and re-firing are performed in the presence of the impurities to be doped.
  • the starting material is doped with the impurities during the two firing processes.
  • the photoconductive alloy obtained in this fashion is in the form of polycrystal.
  • the impurities are introduced into the crystallized alloy by the method such as thermal diffusion method upon completion of the,
  • this method can prevent the mercury from evaporating into the surrounding atmosphere. before'it is introduced into a finished ternary alloy. This is because the mercury once introduced into the ternary alloy Will not leave there and evaporate into the atmosphere.
  • mercury is added in the form of its compound to the starting material containing cadmium and selenium in the form of cadmium selenide, for instance.
  • a solvent flux is further added to the starting material in order to reduce the melting point of the material and therefore to accompli'sh the crystal growth of the material at a reduced temperatur'e.
  • the activator impurity is added to and mixed with the starting material while the coactivator impurity is supplied from the solvent flux.
  • the mercury compound may act as the solvent flux and as a supplier of the coactivator impurity.
  • the amount of the mercury added in the form of its compound to the starting material before the -firing process does not correspond strictly to that of the mercury contained in the finished photoconductive alloy. This is because of the fact that predetermined amount of the mercury added cannot be restrained from evaporating into the ambient atmosphere during the firing process. Consequently, this method is advantageously applied for preparing the photoconductive alloy with decreased content of mercury, namely, with its photosensitivity to the infrared spectral range relatively near the visible light.
  • the photoconductive device which is designated in general as numeral 10, comprises customarily the photoconductive ternary alloy 11 of the form Cd Hg Se, a pair of electrodes 12 mounted on the alloy and spaced from each other and a pair of lead wires 13 attached to the respective electrodes 12.
  • the electrodes 12 are, 1n lIhIS instance, evaporated onto the surface of the photoconductive alloy 11.
  • a suitable voltage of either DC. or AC. type is applied between the two electrodes 12 to produce a photocurrent when irradiated by the infrared ray. This photocurrent is measured to inspect the spectral photosensitivity of the device 10.
  • FIG. 2 showing a series of the characteristic curves of some typical photoconductive alloys to be employed in the device of FIG. 1, the abscissa represents the wavelength of the infrared ray incident on the photoconductive device Whereas the ordinate represents normalized photocurrents of the respective alloys as applicable in the device.
  • FIG. 2 will be given in: the following in connection with the examples, which are given in order that the present invention be more fully understood.
  • the starting material contains g. of cadmium s'el'enid'e and mercury selenide powders of 99.999% purity, 20cc. of 0.001 mole copper salt and 0.5 g. of cadmium halide.
  • the copper salt as applicable in this example is chloride, bromide, iodide or sulphate of copper while the cadmium halide may be any of chloride, bromide and iodide of cadmium.
  • the process used for preparing the photoconductive crystalline ternary alloy comprises the steps of mixing homogeneously the starting material with each other at a temperature of 90 to 100 C. by sutficiently agitating; drying the obtained mixture at aboutl20 C.
  • the activator impurity is copper supplied from the copper salt and the coactivator impurity is halogen supplied from the cadmium halide acting as a solvent flux.
  • the amount of the mercury added to the starting material does not correspond precisely to that of the mercury contained in the finished photoconductive alloy. More specifically, the mercury content in the finished alloy is less than that added at the mixing step. According to the process described in this example, therefore, the finished alloy exhibits photosensitivity in the nearinfrared range. This can be ascertained from observation of FIG. 2.
  • the maximum value of the photocurrent is, from the curve 14 in FIG. 2, below 0.8 micron in wavelength.
  • curves 15 and 16 have their maximum values at 1.0 and 1.05 micron wavelength, respectively.
  • the curves 15 and 16 are obtained from the photoconductive alloys of the invention, containing 25% and 50% by weight of mercury selenide, respectively, in the starting material.
  • the starting material contains 10 g. of cadmium selenide powders of 99.999% purity, cc. of 0.001 mole copper salt and 4 g. of mercury bromide.
  • the copper salt as applicable in this example is chloride, bromide, iodide or sulphate of copper and mercury bromide acting as a solvent flux may be replaced with either of chloride and iodide of mercury.
  • the process used for preparing the photoconductive crystalline ternary alloy comprises the steps of mixing homogeneously the starting material with each other at an elevated temperature by sufliciently agitating; drying the resultant mixture at about C. for 17 hours in an atmosphere of a circulating air; firing the dried mixture at'about 500 C.
  • the activator impurity is copper supplied from the copper salt and the coactivator impurity is bromine supplied from the mercury bromide.
  • the evaporated selenium atmosphere used in the second firing step may be replaced by an evaporated sulphur atmosphere with similar results.
  • the amount of the mercury added to the starting material does not correspond to that of the mercury contained in the completed photoconductive alloy.
  • the alloy obtained possesses a maximum photosensitivity in the near-infrared range, namely, at 1.15 micron wavelength, as indicated by curve 17 of FIG. 2.
  • the photoconductive ternary alloy of the invention may'be utilized for photoconductive devices and elements for detecting the incident infrared rays. These devices are useful in instrumental meters, relays, image converters, pickup devices, switches and so forth.
  • the deviecs comprise customarily the photoconductive alloys of the invention and a pair of electrodes attached to the surface of the alloys. Where the alloys are in the form of polycrystal, suitable resinscan be employed to bond the polycrystalswith each other.
  • the alloys exhibit maximum photosensitivities in the near-infrared range.
  • novel methods for preparing the photoconductive alloys of the invention and photoconductive devices comprising the photoconductive alloys are adapted to prevent the mercury to be added to the photoconductive alloys from evaporating into the surrounding atmosphere during the firing step.
  • the methods can also shift the maximum photosensitivity within a relatively wide range by changing the mercury content in the photosensitive alloys of the invention.
  • Photoconductive crystalline alloy comprising cadmium, mercury and selenium, said alloy having the general formula:
  • Photoconductive crystalline alloy according to claim 1 further comprising an activator selected from the group consisting of copper and silver, and a coactivator selected from the group consisting of chlorine, bromine, iodine, aluminium, gallium and indium.
  • a method for preparing the photoconductive crys talline alloy of claim 1, comprising the steps of: mixing cadmium, mercury and selenium with an activator selected from the group consisting of copper and silver, and a coactivator selected from the group consisting of chlorine, bromine, iodine, aluminium, gallium and indium, and then firing the mixture at a temperature of from about 450 to about 600 C. under atmospheric pressure in air.
  • a method for preparing the photoconductive alloy of claim 1, comprising the steps of: mixing cadmium, mercury and selenium with an activator selected from the group consisting of copper and silver, and a coactivator selected from the group consisting of chlorine, bromine and iodine, aluminium, gallium and indium; and then firing the mixture at a temperature of from about 700 to about 800" C. under a pressure of from about 70 to about 100 atm. in an inert gas atmosphere.
  • a method for preparing a photoconductive crystalline alloy of claim 1, comprising the step of: mixing cadmium, mercury and selenium; firing the mixture at a temperature of from about 450 to about 600 C. in an atmospheric pressure until a homogeneous material is obtained; re-firing the resultant material at a temperature of from about 450 to about 600 C. in atmospheric pressure until the material crystallizes, and then doping the obtained material with an activator selected from the group consisting of copper and silver, and a coactivator selected from the group consisting of chlorine, bromine, iodine, aluminium, gallium and indium.
  • a method for preparing a photoconductive alloy of claim 1, comprising the step of: mixing cadmium, mercury and selenium; firing the mixture at a temperature of from about 700 to about 800 C. under the pressure of from about 1,100 to about l,200 C. under a pressure of from about to about 100 atm. in an inert gas atmosphere until the material crystallizes, and then doping the obtained material with an activator selected from the group consisting of copper and silver, and a coactivator selected from the group consisting of chlorine, bromine, iodine, aluminium, gallium and indium.
  • a method for preparing a photoconductive alloy of claim 1 comprising the steps of: mixing cadmium selenide, mercury selenide, copper salt selected from the group consisting of chloride, bromide, iodide, and sulphate of copper, and cadmium halide selected from the group consisting of chloride, bromide, and iodide of cadmium; drying the mixture; and then firing at least once the resultant mixture at a temperature above the melting point of cadmium halide in an atmosphere of air.
  • a method for preparing a photoconductive crystalline alloy of claim 1, comprising the steps of: mixingv cadmium selenide, mercury halide selected from the group consisting of chloride, bromide and iodide of mercury, and copper salt selected from the group consisting of chloride, bromide, iodide and sulphate of copper, and then firing at least once the mixture at a temperature above the melting point of mercury halide in an atmosphere of air.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Light Receiving Elements (AREA)
US18248A 1969-03-14 1970-03-10 Photoconductive ternary alloy of cadmium,selenium and mercury Expired - Lifetime US3666450A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP44021073A JPS501518B1 (xx) 1969-03-14 1969-03-14

Publications (1)

Publication Number Publication Date
US3666450A true US3666450A (en) 1972-05-30

Family

ID=12044696

Family Applications (1)

Application Number Title Priority Date Filing Date
US18248A Expired - Lifetime US3666450A (en) 1969-03-14 1970-03-10 Photoconductive ternary alloy of cadmium,selenium and mercury

Country Status (7)

Country Link
US (1) US3666450A (xx)
JP (1) JPS501518B1 (xx)
CA (1) CA939593A (xx)
DE (1) DE2011791C3 (xx)
FR (1) FR2038931A5 (xx)
GB (1) GB1307605A (xx)
NL (1) NL152124B (xx)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4086106A (en) * 1977-01-06 1978-04-25 Honeywell Inc. Halogen-doped Hg,Cd,Te
EP0239363A2 (en) 1986-03-25 1987-09-30 Konica Corporation Light-sensitive silver halide photographic material feasible for high speed processing
US20110033368A1 (en) * 2007-10-05 2011-02-10 Agency For Science, Technology And Research Methods of forming a nanocrystal

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4086106A (en) * 1977-01-06 1978-04-25 Honeywell Inc. Halogen-doped Hg,Cd,Te
US4105479A (en) * 1977-01-06 1978-08-08 Honeywell, Inc. Preparation of halogen doped mercury cadmium telluride
EP0239363A2 (en) 1986-03-25 1987-09-30 Konica Corporation Light-sensitive silver halide photographic material feasible for high speed processing
US20110033368A1 (en) * 2007-10-05 2011-02-10 Agency For Science, Technology And Research Methods of forming a nanocrystal

Also Published As

Publication number Publication date
GB1307605A (en) 1973-02-21
DE2011791A1 (de) 1970-09-24
NL152124B (nl) 1977-01-17
CA939593A (en) 1974-01-08
NL7003608A (xx) 1970-09-16
DE2011791B2 (de) 1974-01-17
DE2011791C3 (de) 1974-08-08
JPS501518B1 (xx) 1975-01-18
FR2038931A5 (xx) 1971-01-08

Similar Documents

Publication Publication Date Title
US3467548A (en) Method of making xerographic plate by vacuum evaporation of selenium alloy
FR3004467A1 (fr) Fabrication d'une elpasolite stoechiometrique
US3666450A (en) Photoconductive ternary alloy of cadmium,selenium and mercury
KR20220021118A (ko) 와이드 밴드갭을 가지는 페로브스카이트 박막의 제조 방법, 이에 의해 제조된 페로브스카이트 박막, 이를 포함하는 태양전지
US3984722A (en) Photoconductive target of an image pickup tube and method for manufacturing the same
US3962141A (en) Vitreous photoconductive material
US3110685A (en) Semiconductive materials containing thallium
Dowman et al. Scanning electron diffraction studies on alkali antimonide photocathodes, including the S20
Fair Jr et al. Optical and electrical properties of thin films of α-lead azide
US3598760A (en) Cdse or cds-se photoconductors doped with a ib element and either bromine or iodine
Kaifu et al. Some optical properties of CuCl single crystals
Kawaguchi et al. Composition dependence of Ag photodoping into amorphous Ge‐S films
US4601965A (en) Photosensitive material for use in electrophotography
US3092725A (en) Blocking-layer photo-electric cell
US3598750A (en) Photochromic image device
US4263056A (en) Method for the manufacture of light emitting and/or photodetective diodes
US3691104A (en) Process for preparing photoconductive powders
US3483028A (en) Preparation of light sensitive device of enhanced photoconductive sensitivity
US3704265A (en) Sintered inorganic photoconductive elements and their method of preparation
US3820988A (en) Method of sensitizing zinc telluride
Fonda The Yellow and Red Zinc Silicate Phosphors.
US3666554A (en) Manufacture of electrophotographic plate
SU1051490A1 (ru) Электрофотографический материал
US3133888A (en) Production of semiconductor materials
Ordinartsev et al. Sub-and supersolidus phase relations of formamidinium-cesium polyiodides