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Publication numberUS3858074 A
Publication typeGrant
Publication dateDec 31, 1974
Filing dateNov 6, 1972
Priority dateNov 9, 1971
Also published asCA976265A, CA976265A1, DE2254605A1, DE2254605B2, DE2254605C3
Publication numberUS 3858074 A, US 3858074A, US-A-3858074, US3858074 A, US3858074A
InventorsO Eguchi, S Fujiwara, M Fukai, Y Kuramoto, H Serizawa
Original AssigneeMatsushita Electric Ind Co Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Photoelectric transducer element including a heterojunction formed by a photoelectric transducer film and an intermediate film having a larger energy gap than the photoelectric transducer film
US 3858074 A
Abstract
A photoelectric transducer element having high photo and spectral sensitivity in which a material with an energy band gap larger than that of a photoelectric transducer film is interposed between the photoelectric transducer film and a transparent conductive film.
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Description  (OCR text may contain errors)

United States Patent 1191 Fukai et a1.

[ 1 Dec. 31, 1974 Matsushita Electric Industrial Co. Ltd., Kadoma-shi, Osaka, Japan Filed: Nov. 6, 1972 Appl. 010.; 304,050

Assignee:

Foreign Application Priority Data Nov. 9, 1971 Japan 46-89622 Dec. 29, 1971 Japan 47-3265 Sept. 25, 1972 Japan 47-96428 US. Cl 313/94, 252/623 ZT, 357/16,

357/30, 357/61 Int. Cl. H01j 39/06, H011 9/00 Field of Search 313/94, 96, 65 AB;

317/235 AC, 235 NA, 235 AP, 235 A0; 250/211 J; 338/15; 252/623 ZT [56] References Cited UNITED STATES PATENTS 3,287,611 11/1966 Bockemuehl 317/235 AQ 3,346,755 10/1967 Dresner 313/94 3,405,298 lO/1968 Dresner 317/241 OTHER PUBLICATIONS Morehead et a1., Efficient, Visible Electroluminescence From p-n junctions in Zn Cd Te App Physics Letters, Vol. 5, 1964, pp. 53-54.

Abrikosov et a1., Semiconducting lI-Vl, lV-Vl &

V-VI, Compounds Plenum press, N.Y., 1969, pp. 26-28, QC612, S4P6. Tansley, T. L. Heterojunction Properties, Chapt. 6 of Semiconductors & Semimetals, Academic Press, N.Y. & London, 1971, Vol. 7, part A. pp. 299-309 QC612, S4W5.

Primary Examiner-lames W. Lawrence Assistant ExaminerWm. H. Punter Attorney, Agent, or Firm-Stevens, Davis, Miller & Mosher 57] ABSTRACT A photoelectric transducer element having high photo and spectral sensitivity in which a material with an energy band gap larger than that of a photoelectric transducer film is interposed between the photoelectric transducer film and a transparent conductive film.

11 Claims, 9 Drawing Figures SPECTRAL SENOSITIVITY (,u w) T APPLIED VOLTAGE 30V PATENTEB UEC3 1 I974 SHEET 10F 5 FIG.2

6000 8000 o WAVE LENGTH (A) PAIENIEUHECBHBH 3.858.074

SHEET 2 UF 5 Xe LAMP LIGHT souRcE XAND FILTER F I 4 SHUTTER 5' ELECTROMAGNETIC RL AMPL- OSCILLOGRAPH SYNCHROSCOPE VT I 5 aw F l G. 5 10) E j 30 v l "5- EE DU o 'z'o'4b'eb'o' n e e COMPOSITION F l G. 6

(XIO A 5 o 0.36 Lux E E 30 V lhi as 2 0 SE W-LAMP I: 0.0

0 2O 4O 6O 8O ZnTe COMPOSITION PATENTEDBEBII 1 IBM 3, 858,074

SHEET 3 OF 5 FIG. 7

APPLIED VOLTAGE 30V SPECTRAL SENSITIVITY [LA/PW) S WAVE LENGTH 1K PATENTEDIJEBIH I974 3,858,071}

SHEET 0F 5 FIG. 8 V

(Znos Cdo.4Te) (In2Te3) APPLIED VOLTAGE 30V SPECTRAL SENOSITIVITY (/LA/FW) T WAVE LENGTH Z PATENTEU 1 I974 SPECTRAL SENSITIVITY #MLW) SHEET 5 i'lF 5 F I G. 9

APPLIED VOLTAGE 30v WAVE LENGTH (,3)

PHOTOELECTRIC TRANSDUCER ELEMENT INCLUDING A HETEROJUNCTION FORMED BY A PHOTOELECTRIC TRANSDUCER FILM AND AN INTERMEDIATE FILM HAVING A LARGER ENERGY GAP THAN THE PHOTOELECTRIC TRANSDUCER FILM The present invention relates to a photoelectric transducer element, or more in particular to a photoelectric transducer element suitably used as a target for an image pickup tube.

CdS, CdSe and mixed crystals thereof are well known as materials suitable for a photoelectric transducer ele' ment. In spite of their high sensitivity, however, they can not be used as a target of an image pickup tube due to considerable dark current accompanying them and their slow responsiveness to light. Also, their spectral sensitivity is low for wavelengths other than those corresponding to their energy band gaps, and materials with a spectral sensitivity curve which is flat over the entire range of visible light have yet to be developed.

Well-known conventional materials used as targets for image pickup tubes include a film of antimony trisulfide Sb S for vidicons, lead oxide PbO for PbO vidicons and a silicon photodiode array for silicon vidicons. All of these materials, however, have their problem points as mentioned below.

1. Vidicons The vidicon has the sensitivity in the order of 200 to 300 ptA/lm and the dark current of 20 nA per one'inch vidicon, and is used as a camera for industrial television, but its low sensitivity limits the images capable of being picked up to those of brightness in the order of 5 1x or more. Another disadvantage of the vidicon is a considerable amount of undesirable afterimage and lay-image accompanying the pickup operation, making it unsuitable for use with a color image pickup tube for television broadcasting.

2. PbO vidicon With a very small amount of dark current of 0.2 nA/l.5 inches and a little lay-image, this is widely used with an image pickup tube for television broadcasting. But its sensitivity is as low as 300 uA/lm which is a little higher than that of the vidicon but still inadequate. Since this has no spectral sensitivity for a red light with wavelength of 650 nm or more, the use of this PbO vidicon for the red color image pickup tube of the threetube type camera requires PbS to be added to PbO so as to increase its sensitivity to about 850 nm. The sensitivity and lag-image of this image pickup tube, however, do not coincide with those of the other tubes of the camera, resulting in the lack of balance among the three tubes. Further, it is impossible to use this image pickup tube for a singledube camera since it has only a small range of spectral sensitivity.

3. Si vidicon This image pickup tube has the advantages of a sensitivity 20 times that of the vidicon and the absence of undesirable after-image. But is characteristics associated with lag-images and resolution are inferior to those of the PhD vidicon, making it unsuitable for use with an image pickup tube for television broadcasting. Another disadvantage of this tube lies in that the peripheral portions of an image of a very bright object are blurred thereby to undesirably enlarge the image to a size two or three times the original image.

Accordingly, it is an object of the present invention to provide a photoelectric transducer element suitable for the target of an image pickup tube and having a high sensitivity and superior property of spectral sensitivity.

The photoelectric transducer element according to the present invention is characterized in that a material with an energy band gap larger than that of a photoelectric transducer film is interposed between a transparent conductive film and the photoelectric transducer film.

The above and other objects, features and advantages will be made apparent by the detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a sectional view showing an embodiment of the present invention;

FIG. 2 is a diagram comparing the spectral sensitivity of a photoelectric transducer element with a ZnSe film interposed between the transparent conductive film and the photoelectric transducer film with that of a photoelectric transducer element without any ZnSe film interposed;

FIG. 3 is a diagram showing the spectral sensitivity of ZnSe-Zn,,Cd,.,,Te;

FIG. 4 is a diagram showing the principle on which the responsiveness to light is measured;

FIG. 5 is a graph showing how the dark current varies with the composition of ZnSe-(Zn,,Cd,. u )0.9s( 2 a)0.o.-s;

FIG. 6 is a diagram showing how the photoelectric current varies with the composition of the ZnSeu 1-u )o.95( z alopsi FIG. 7 is a diagram showing the spectral sensitivity of the photoelectric transducer element consisting of Zny l-J/ )0.95( 2 3)0.05;

'FIG. 8 is a characteristic diagram showing the spectral sensitivity of the photoelectric transducer element consisting of ZnSe-(Zn Cd Te),(ln Te and FIG. 9 is a characteristic diagram showing the spectral sensitivity of the photoelectric transducer element Consisting Of ZIIS SC AZn CCl T) I11 Tc Referring to FIG. 1, a transparent conductive film 2 of, say, In O or SnO is formed on a glass substrate 1, and a photoelectric transducer film 4 is formed on the transparent conductive film 2 with an intermediate film 3 therebetween having an energy band gap larger than that of the photoelectric transducer film 4. A heterojunction is formed by the intermediate film 3 and the photoelectric transducer film 4.

The facts that must be taken into consideration in selecting the material for the intermediate film 3 are (1) that the lattice constant, crystal structure and the coefficient of thermal expansion of the intermediate film approximate those of the photoelectric transducer film and (2) that the band structure of the intermediate film 3 and the photoelectric transducer film are capable of being connected smoothly with each other when they are bonded together. These conditions must be met to improve the photoelectric transducing efficiency by improving the crystal quality of the surface of that side of the photoelectric transducer film from which light enters and thereby reducing the surface state due to lattice defects. Light with a wavelength shorter than one corresponding to the energy band gap of the photoelectric transducer film is absorbed by the photoelectric transducer film at a portion very near its surface. If this portion has a low crystal quality with many recombination centers present in that portion, a low photoelectric transducing-efficiency results.

The results of experiments conducted by the inventors show that the energy band gaps of the intermediate film 3 and the photoelectric transducer film 4 determine the limits of short and long wavelength respectively for which the spectral sensitivity is effective. FIG. 2 shows the results of the test in which the characteristic of the photoelectric transducer film 4 of (Zn Cd Te)0 9 (In Tc3)0 05 with the intermediate film 3 of ZnSe is compared with the photoelectric transducer film of the same substance without the intermediate film 3 of ZnSe. In this figure, curve I is the case without any ZnSe film and curve II with the ZnSe film. It will be easily understood from this drawing that curve II associated with the transducer film with the ZnSe film represents a spectral sensitivity for short wavelengths much higher than curve I showing the characteristic of the transducer film in the absence of the ZnSe film. Also, it was found that the use of the ZnSe film reduces the dark current. Further, as a result of comparison, on a replica photograph taken under the electronic microscope, between a first photoelectric transducer element with the intermediate film of ZnSe laid between the glass substrate and the photoelectric transducer film of 500 A. ahd a second photoelectric transducer element without any intermediate film, it was made clear that the grain size of the transducer element with the ZnSe film is larger than that without any ZnSe film.

Before reference is had to embodiments of the present invention, explanation will be made below of the methods of manufacturing and measuring the characteristics of the photoelectric transducer element which were commonly applied to all of the embodiments.

First, several depositing heaters are placed in a depositing means and such a depositing material as ZnS, ZnSe, ZnTe, CdTe, ln Te or their solid solution is applied to the heaters. By controlling the temperature of the heaters, a solid solution of a desired composition is made. The availability of several heaters permits the manufacture of a composite film without affecting the vacuum condition. A glass substrate with the transparent conductive film attached thereto is heated to 100 to 400C thereby to deposit the solid solution of the above-mentioned composition on it by evaporation. The resulting assembly is heated at 300 to 700C for from several minutes to several hours to produce a photoelectric transducer element.

The dark current, photoelectric current, responsiveness to light and spectral sensitivity of the photoelectric transducer element thus produced and with an electrode formed on that side having the photoelectric transducer film were measured, the results of which are as follows:

a. Spectral sensitivity An interference filter and a halogen lamp of 3400K were used to measure the photoelectric current at regular intervals of 200 A. The amount of light applied to the specimen through the filter from a light source was measured by means of a thermopile.

b. Dark current and photoelectric current The current-voltage characteristic as well as the photoelectric current-illumination characteristic were measured with the Electrometer Model 610C of keithley.

c. Responsiveness to light The response to light of an image pickup tube is different from the photoconductive response of an element thereof in principle. The inventors have prepared an equivalent circuit which requires no electron beam, associated with a picture element of the image pickup tube scanned by an electron beam, thereby to evaluate the characteristics of the image pickup tube through an element. The principle of the evaluation is as shown in FIG. 4, in which the photoelectric tube 5 is seen to be turned on and off by a light pulser with a pulse width of 2 us at 60 Hz so as to apply an electron beam to a picture element at 60 Hz. Light of 0.4 lx was radiated on the element from another light source of the halogen lamp of 3,400K so that the responsiveness to light was measured with a shutter usually used for photographing. The results of the measurements mentioned above coincide pretty well with those of measurements conducted on an image pickup tube assembled from the element. The measurements were made in terms of a rise and fall in 50 ms after the application and shutting off the light respectively.

d. Composition of the deposited film The composition of the deposited film was measured by solid mass analysis and activation analysis.

After measuring the characteristics of the element as above, the characteristics of the image pickup tube were determined as follows:

a. Dark current and photoelectric current:

A positive voltage was applied to that side of the image pickup tube to which the transparent conductive film is attached, during the scanning by an electron beam, and a signal current taken out of the transparent conductive film was measured.

b. Lag-image and after-image:

A lag-image is a transient phenomenon representing the magnitude of a signal current remaining 50 ms after shutting light off. It occurs during the transition stage from a bright to dark state and is generally expressed in the percentage of a signal remaining at a time point 50 ms after shutting light off. An afterimage is a term indicating a time period, as observed by a display monitor, needed for an image of an object to be extinguished on a uniformly white background which was picked up after picking up the object for a predetermined period of time under a standard pickup condition.

Embodiments of the present invention will be now explained. Embodiment l:

A photoelectric transducer element was used which comprises a heterojunction of an intermediate film of ZnS Se and a photoelectric transducer film of Zn Cd fFe and experiments were conducted by varying the value y of Zn Cd Te while maintaining it of ZnS Se at zero.

As shown in FIG. 1, the assembly comprising a glass substrate 1 with a transparent conductive film 2 deposited on it was heated to and maintained at the temperature of to 400C, andZnSe, that is ZnS,.Se with x at zero, is deposited by evaporation into the thickness of 0.02 to 2 microns on the transparent conductive film 2 for 5 to 30 minutes. On this ZnSe film 3 is formed a solid solution 1 to 20 X 10" m thick by evaporation in a pair of melting pots containing ZnTe and CdTe respectively, while maintaining the temperature of the substrate at 150 to 300C for 5 to 60 minutes. The value of y of the solid solution may be varied by controlling the temperature of the melting pots. A composa le i the ralsensit vity o an bz s As can be seen from this figure, the effect of spectral sensitivity extends further toward long wavelengths, the greater the amount of Cd relative to that of Zn. This is because the band gap is decreased with an increase in the amount of Cd. As a result, it is possible, by appropriately selecting the value of y, to obtain a photoelectric transducer element with a spectral sensitivity over the entire range of visible light. I

The characteristics of a one-inch image pickup tube employing the photoelectric transducer element according to the present invention are compared with those of the conventional Sb S vidicon in Table 1 below.

It will be noted from this table that the sensitivity of the image pickup tube according to the present invention is 2 or 3 times higher than that of the conventional vidicon. Further, with the increase in the amount of Cd, the sensitivity is improved but the dark current is also increased. There are less lagimage with the increase in the amount of Cd. All this tells that the photoelectric transducer element according to the present invention has a higher sensitivity and a broader range of spectral sensitivity than the Sb S vidicon.

Furthermore, it was found that not only the spectral sensitivity for short wavelength is improved but the range of spectral sensitivity broadened and the sensitivity itself improved by replacing the intermediate film of ZnSe by a film of ZnS or the solid solution consisting of ZnS and ZnSe.

Embodiment 2 This embodiment has the same structure as embodiment 1, employing an intermediate film of ZnS Se as in embodiment 1 while it is different from embodiment l in that Zn,Cd1.,,Te with In added thereto is used as a photoelectric transducer film. When the amount of In added to the photoelectric transducer film of Zn Cd Te was changed from lXl0"/cc to 2Xl0 /cc, in the presence of an intermediate film of ZnSe, dark current which occurred in the photoelectric transducer element is as shown in Table 2 below From this experiment, it is known that the dark current tends to decrease with'theincrease in the amount of indiumadded to the photoelectric transducer film.

It was found that, if the solid solution of Zn Cd Te remains unchanged, the spectral sensitivity also remains almost the same, but when the amount of indium added is higher than 10 /cc, the sensitivity curve extends toward long wavelength. The absolute value of the sensitivity has sharply increased with the increase in the amount of in added. The representative characteristics of a one-inch image pickup tube witha target employing an element of the above-mentioned materials are shown in Table 3.

As'will be apparent from this table, the sensitivity rises considerably with the increase in the amount of indium added, while dark current decreases, with the result that the S/N ratio for the photoelectric transducer film obtained by adding indium in the amount of 2 l0 /cc in an evaporation source is improved by more than one order. Lag-images have remained almost the same.

As in embodiment l, the spectral sensitivity for short wavelength can be improved and the range of wavelength over which the sensitivity is effective can be broadened by replacing the intermediate film of ZnSe with a solid solution of ZnS Se As to the long wavelength side, the sensitivity may be extended to a desired A wavelength by changing the ratio between Zn and Cd of the photoconductive film.

In the above-described experiment, the deposited film was made in the same way as in embodiment l by adding indium to the Zn Cd Te through thermal diffusion and the amount of indium is shown in terms of the quantity placed in an evaporation source. The results of mass analysis show, however, that where a solid solution of Zn Cd Te containing indium in the amount of 2 X lO lcc is used as an evaporation source, 3.2 atomic percent of indium is contained in the deposited film. On the other hand, where a solid solution containing 2 X l0 /cc of indium is used, the deposited film contains 0.02 atomic percent of indium. Embodiment 3 the intermediate filmland the photoelectric transducerfilm respectively as in embodiment 1. Experiments were conducted by varying the value of x, y and z separately. Since the structure and the method of manufacture of the photoelectric transducer element are the same as in embodiment 1, only the results of the experiment and advantages of the present embodiment will be mentioned below. u l-u )0.95( 2 3)0.05

First, reference is made to a photoelectric transducer element with the intermediate film of ZnSe and a photoelectric transducer film of a varying ratio between Zn and Cd. With 5 percent of In Te added, experiments were conducted on the six values of y, i.e. 0.9, 0.8,

0.75, 0.7, 0.5 and 0.3, the results of which are shown below.

a. Dark current How dark current depends on the value of y is shown in FIG. 5. It is seen that the dark current becomes minimum when y is 0.7 to 0.8 and it sharply increases at a t iise lx y rlbaaQ- or -8- b. Sensitivity The value y affects the sensitivity in such a manner as shown in FIG. 6. Although it must be admitted that different sensitivities result from different methods of manufacturing the element, it is apparent that the sensitivity rises with the decrease in the value of y.

Table -Continued y 0.6 y 0.7 resolution 780 780 illumination (l E") r 0.95 r 0.95

Table 4 The dark current tends to rise when 1 is smaller than 0.85, while it remains almost the same when z is between 1 and 0.85. The sensitivity remains almost unchanged when 1 is between 1 and 0.85. The response is quick for all of the values of Z and it is quicker the higher the applied voltage. When z is smaller than 0.7, a phase of ln Te was detected in the deposited film as a result of X-ray analysis. The presence of the phase causes a great dark current, thereby making the element unsuitable for a target of the image pickup tube. Namely,'030 mol percent of ln Te is suitable for the An example of responsiveness Volts Comp.

y=0.8 89/25 78/18 80/17 82/15 rise(%)/fall(%) y=0.7 86/17 81/13 85/11 under 0.4 lx y=0.5 39/11 92/10 after msec.

Table 5 sensitivity (PA/1m) 4000 3840 dark current (nA) 5 4 lag-ima es l2 l4 residu images nil nil after-images nil nil target of the image pickup tube. The sensitivity remains almost unchanged when Z is between 1 and 0.85 as shown in FIG. 8. .r 1-.r'( o.s 0.4 )0.ss( 2 3)o.0s

Experiments were conducted for various values of x in ZnS Se For all values ofx including 0.5, 0.7 and 1.0 dark current, sensitivity and responsiveness all remained almost the same as in the preceding embodiment, while the spectral sensitivity for short wavelength is increased with the value of x as shown in FIG. 9. The element with x of unity is suitable for an ultra-violet ray camera as it has a sufficiently high sensitivity for the ultra-violet range.

It will be understood from above that the abovementioned image pickup tubes embodying the present invention have a higher sensitivity than the conventional vidicon and PbO vidicon, and the target includedin the embodiments has an almost flat curve of spectral sensitivity over the entire range of visible light, making it possible to apply the present invention to a singletube color image pickup tube.

Since the photoelectric transducer element according to the present invention is high both in photosensitivity and spectral sensitivity, it can be used not only as a target of the image pickup tube but as a photoelectric transducer film for electronic photograph and illumination photometer.

The reason why the present invention is characterized by a high photosensitivity and spectral sensitivity is the interposition between the transparent conductive film and the photoelectric transducer film of an intermediate film with a larger energy band gap than the photoelectric transducer film, which not only permits the portion sensitive to light, that is, the crystal structure at the junction between the photoelectric transducer film and the intermediate film to be improved but also allows light with a longer wavelength than the one corresponding to the energy band gap of the intermediate film to enter the photoelectric transducer film without loss.

As is apparent from the above explanation of the embodiments, the photoelectric transducer element according to the present invention has a higher photosensitivity as well as higher spectral sensitivity without any lag-images, residual images or undesirable after-image.

What is claimed is:

l. A photoelectric transducer element and a target for an image pickup tube using said element, comprising a photoelectric transducer film, a transparent conductive film, a material interposed between said photoelectric transducer film and said transparent conductive film, and a heterojunction of said photoelectric transducer film and said material, said material having a larger energy gap than said photoelectric transducer film, said photoelectric transducer film containing Z n Cdb Te (0.l y0.9) as a main component, and said material containing ZnS,Se,. gxg l) as a main component.

2. A photoelectric transducer element and a target for an image pickup tube using said element according to claim 1, wherein said photoelectric transducer film containing Zn Cd,.,,Te (0.l gy; 0.9) as the main component further contains indium added thereto.

3. A photoelectric transducer element and a target for an image pickup tube using said element according to claim 2, wherein said photoelectric transducer film containing Zn Cd Te (0.1 gyg 0.9) as the main component contains 0.02 to 3.2 atomic percent of indium added thereto,

4. A photoelectric transducer element and a target for an image pickup tube using said element according to claim 1, wherein said photoelectric transducer film containing Zn Cd,.,,Te (0.l yg 0.9) as the main component further contains 30 mol% or less of a compound of In and Te added thereto.

5. A photoelectric transducer element and a target for an image pickup tube using said element, comprising a photoelectric transducer film, a transparent conductive film, a material interposed between said photoelectric transducer film and said transparent conductive film, and a heterojunction of said photoelectric transducer film and said material, said material having a larger energy gap than said photoelectric transducer film, said photoelectric transducer film containing Zn Cd Te (0 g y; 1) as a main component and further containing 30 mol percent or less of a compound of In and Te added thereto, said photoelectric transducer film having the formula and said material containing ZnS,,-Se,- ,-(0 5 x 2 l) as a main component.

6. A photoelectric transducer element and a target for an image pickup tube using said element according to claim 5, wherein x 0 and z 0.95.

7. A photoelectric transducer element and a target for an image pickup tube using said element, comprising a photoelectric transducer film, a transparent conductive film, a material interposed between said photoelectric transducer film and said transparent conductive film, and a heterojunction of said photoelectric transducer film and said material, said material having a larger energy gap than said photoelectric transducer film, said photoelectric transducer film containing Zn Cd Te (0.5 i y 2 0.8) as a main component and further containing 30 mol percent or less of a compound of ln and Te added thereto, said photoelectric transducer film hhaving the formula and said material containing ZnSe as a main component.

8. A photoelectric transducer element and a target. for an image pickup tube using said element according to claim 5, wherein x 0 and y 0.6.

9. A photoelectric transducer element and a target for an image pickup tube using said element, comprising a photoelectric transducer film, a transparent conductive film, a material interposed between said photoelectric transducer film and said transparent conductive film, and a heterojunction of said photoelectric transducer film and said material, said material having a larger energy gap than said photoelectric transducer film, said photoelectric transducer film containing Zn Cd Te as a main component and further containing 30 mol percent or less of a compound of [n and Te added thereto, said photoelectric transducer'film having the formula and said material containing ZnSe as a main component.

10. A photoelectric transducer element and a target for an image pickup tube using said element according to claim 5, wherein y 0.6 and z 0.95.

11. A photoelectric transducer element and a target for an image pickup tube using said element according to claim 10, wherein x l.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3287611 *Aug 17, 1961Nov 22, 1966Gen Motors CorpControlled conducting region geometry in semiconductor devices
US3346755 *Mar 31, 1966Oct 10, 1967Rca CorpDark current reduction in photoconductive target by barrier junction between opposite conductivity type materials
US3405298 *Mar 4, 1965Oct 8, 1968Rca CorpPhotoconductive device having a target including a selenium blocking layer
Non-Patent Citations
Reference
1 *Abrikosov et al., Semiconducting II VI, IV VI & V VI, Compounds Plenum press, N.Y., 1969, pp. 26 28, QC612, S4P6.
2 *Morehead et al., Efficient, Visible Electroluminescence From p n Junctions in Zn Cd TE App. Physics Letters, Vol. 5, 1964, pp. 53 54.
3 *Tansley, T. L. Heterojunction Properties, Chapt. 6 of Semiconductors & Semimetals, Academic Press, N.Y. & London, 1971, Vol. 7, part A. pp. 299 309 QC612, S4W5.
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3985918 *Jan 23, 1975Oct 12, 1976Matsushita Electric Industrial Co., Ltd.Method for manufacturing a target for an image pickup tube
US4589192 *Nov 2, 1984May 20, 1986The United States Of America As Represented By The Secretary Of The ArmyHybrid epitaxial growth process
Classifications
U.S. Classification313/385, 252/62.3ZT, 257/614, 257/E31.67, 257/201, 257/78
International ClassificationH01L31/102, H01J29/45, H01L31/109, H01J29/10
Cooperative ClassificationH01L31/109, H01J29/45
European ClassificationH01J29/45, H01L31/109