US2862126A - Radiation sensitive semi-conductive layer of amorphous selenium - Google Patents

Radiation sensitive semi-conductive layer of amorphous selenium Download PDF

Info

Publication number
US2862126A
US2862126A US377214A US37721453A US2862126A US 2862126 A US2862126 A US 2862126A US 377214 A US377214 A US 377214A US 37721453 A US37721453 A US 37721453A US 2862126 A US2862126 A US 2862126A
Authority
US
United States
Prior art keywords
selenium
ray
layer
amorphous selenium
sensitive
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
US377214A
Inventor
Ploke Martin
Keller Manfred
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.)
Zeiss Ikon AG
Original Assignee
Zeiss Ikon AG
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
Priority to GB22985/53A priority Critical patent/GB748302A/en
Application filed by Zeiss Ikon AG filed Critical Zeiss Ikon AG
Priority to US377214A priority patent/US2862126A/en
Application granted granted Critical
Publication of US2862126A publication Critical patent/US2862126A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/06—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/26—Measuring radiation intensity with resistance detectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
    • H01J29/36—Photoelectric screens; Charge-storage screens
    • H01J29/39—Charge-storage screens
    • H01J29/45—Charge-storage screens exhibiting internal electric effects caused by electromagnetic radiation, e.g. photoconductive screen, photodielectric screen, photovoltaic screen
    • H01J29/458—Charge-storage screens exhibiting internal electric effects caused by electromagnetic radiation, e.g. photoconductive screen, photodielectric screen, photovoltaic screen pyroelectrical targets; targets for infrared or ultraviolet or X-ray radiations
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/20—Manufacture of screens on or from which an image or pattern is formed, picked up, converted or stored; Applying coatings to the vessel
    • H01J9/233—Manufacture of photoelectric screens or charge-storage screens
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02612—Formation types
    • H01L21/02617—Deposition types
    • H01L21/02631—Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation

Definitions

  • Semi-conductive layers consisting of amorphous selenium have hitherto been used for measuring of radiation only.
  • semi-conductive layers consisting of amorphous selenium were used which had been made sensitive for X-rays through a prolonged special treatment of the selenium.
  • Said special treatment consisted at least partially in transformation of the amorphous character of the selenium into the crystalline condition, whereby a selenium was obtained which had a low ohmic resistance.
  • selenium resistant cells known as Fiirstenau Roentgen radiation intensity measuring devices show too great an inertia, fatigue and ageing in connection with X-rays.
  • the reason'for these phenomena is connected with the crystalline intercalation'of amorphous selenium layers.
  • the required inertia-free receptivity for X-rays is due to the fact that, the X-ray electric effect, contrary to the radiation-electric effect, depends upon an intra-atomic process for the inception of which the small amountof energy in the radiation is insuficient. Therefore, the radiation sensitivity is, according to earlier perceptions, coupled with the crystalline condition of the matter even if in small traces only.
  • cold-evaporated layers are extremely insensitive to light as distinguished from layers which have been evaporated on a support having a temperature of, for example, 175 F.
  • Said cold-evaporated layers have the adidtional advantage that their resistance in the dark is one to two units higher than that of hot-evaporated layers, which is of essential importance for their use as a charge feeding layer.
  • Fig. 1 is a diagram showing the relation between X-ray conductivity and thickness of a selenium layer according to the invention
  • Fig. 2 is a perspective view, partly in section, of a longitudinal cell comprising an amorphous selenium layer
  • Fig. 3 is a perspective view,-partly in section, of a highohmicX-ray resistance cell according-to the invention
  • Fig. 4 shows an X-ray image iconoscope according to the invention
  • Fig. 5 shows the invention applied to a conventional orthicon tube
  • Fig. 6 shows a cross sectional view of a modified construction and arrangement of the semi-conductive layer and support of the invention
  • Fig; 7 shows a modified arrangement of the construction shown in Fig. 6.
  • the X-ray sensitive element which, according to the invention, consists of a layer of amorphous selenium, has a high sensitivity for X-rays, said layer has to be applied in relatively great thickness.
  • the earlier light sensitive semi-conductive layers of selenium which were applied in a thickness from 1 to 10 microns have very low X-ray sensitivity.
  • the X-ray conductivity of the amorphous selenium layers is dependent upon the layer thickness to an extremely high degree.
  • FIG. 1 shows the established X-ray conductivity coefiicient am
  • a glass plate 1 served as carrier for these layers.
  • the amorphous selenium layer 2 is disposed between two evaporated aluminum electrodes 3 and 4.
  • a circuit isclosed. From the current and the imposed voltage the conductivity change in the cell under X-ray radiation is calculated and therefrom also the X- ray conductivity coefiicient oz in a a 1 82 cm. mr./sec.
  • the X-ray radiation was obtained as a 60 kv. continuous radiation from an X-ray tube with a' olfram anti-cathode.
  • the X-ray conductivitycoefiicient is thereby related to the received dosage effect in mr. per second. No appreciable dependence .of the X-ray conductivity coeificient upon the hardness of radiation exists between 50 and kv.
  • the dependency of the X-ray conductivity coefficient upon the thickness of the layer runs approximately parallel with the absorbed X-ray radiation in the selenium layer. With the radiation employed, the highest X-ray conductivity coefiicient is obtained at a thickness of the selenium layer of about 300 microns and, therefore, it is not advisable to make the layers thicker than 300 microns.
  • X-ray sensitive amorphous selenium layers may be used in a variety of apparatus, two embodiments being described below.
  • Fig. 3 shows a perspective view, partly in section, of a high-ohmic X-ray resistance cell accord ing to the invention. This cell is produced by precipitating an amoiphous selenium layer 6 of a thickness of, for example, 200 microns on a metal support plate 7. A metal layer 8 penetra-ble by X-ray radiation is placed on said selenium layer as a counter-electrode. .As electrodes, materials are used which do not react with selenium such as, for example, aluminum, nickel, lampblack, graphite, or carbon.
  • Fig. 4 shows an X-ray image iconoscope, the. semiconductive layer of which is formed according to the in vention as an X-ray sensitive amorphous selenium layer,
  • the iconoscope has a bulb 11 of glass'or aluminum which for the purpose of less absorption of the X-ray image is spherical, so that it may be produced with less wall thickness.
  • a material having a lower absorption coeflicient than glass is used, for example, berryllium glass, or so called Lindernann glass.
  • the screen electrode has a conductive signal plate 12 which is transparent for X-ray radiation.
  • a signal plate for example, a thin aluminum sheet may serv e.
  • Said signal plate carries the X-ray sensitive seleniumlayer lfi.
  • a suitable thickness of the amorphous selenium layer 13 is between 50 microns and .300 microns. ,'l .”he signal plate and theiX-ray sensitive selenium layer may also be applied directly to the tube bulb.
  • the signal plate is supplied with a biasing potential.
  • said biasing potential maybe- 600 v. orlrnore. ln order to interrupt the induced conductivity producedby the scanning ray, it may be advisable toprovide the free surface of the amorphous selenium layer with a mosaic 25 which is impenetrable for the electrons ofthe scanning ray.
  • the load images produced on the free selenium surface through change of resistance in the X-ray sensitive selenium layer are supplied to the image amplifier 16 through the scanning by means of the. electron ray in a known way over the coupling condenser 15.
  • An acceleration electrode 17 suitably comprising a fine mesh net or metal ring is disposed betweenthe signalplate 12 and the scanning aperture 24 of the ray system.
  • suitable elements are provided forproducing an electron ray bundle. They consist of a cathode 18 with a heating wire 19, the Wehnelt cylinder 20 and the anode 21.
  • the electron ray is finely restricted in order to'improve the resolving power of the iconoscope.
  • Bartspfjhe inner surface of the glass bulb are coatedwith .a conductive material so as .to deflect. charges onthe glasswall. Since the X-ray images reach the selenium layer in their natural size, a good dissolution capacity canbe obtained with the iconoscope. Due to the largedeflecting amplitudes, it is necessary to provide for particularly good magnetic screening. 7
  • a function with orthicon electron optics is also possible as shown in Fig. 5.
  • the X-ray sensitive layer 12 with its support 13 is mounted in the envelope of a conventional orthicon tube 11a which is surrounded by the customary longitudinal focusing coil 23a, while in place of the coil 22 employed in Fig. 4 there is used with the orthicon tube 11a an adjustment coil 22a.
  • heavy metals or heavy metal selenium-compounds may be mixed with the selenium such as, for example, lead or leadselenide.
  • Lead selenide is known as a high-ohmic light sensitive substance.
  • the proportion of said heavymetals in the amorphous selenium layer should be variable from minimum amounts to the stoichiometric relationof the corresponding selenide in order to obtain the most advantageous composition for the responsiveness of the resistance layer to X-rays under all conditions.
  • the useability of said foreign ingredients transversely to the maximum extension of the layer is included, for example, so that the side of the layer opposite to the X-rays consists of pure selenium, while the side of said layer facing the X-rays has an increasing proportion of foreign ingredients or selenides 13a, respectively as shown in Fig. 6. .
  • the selenides having advantageous photoelectric qualities silver selenide occupies a prominent position.
  • the cells As resistance scanners, it may also, under certain circumstances, be suitable to enrich the side opposite the X-ray with foreign metals 13b (Fig.7) since. the side facing the scanning ray, that is, the side opposite the X-ray, must have the lower conductivity. Said two considerations may be combined'if the scanning takes place from the side of the X-ray radiation.
  • the surface activation of selenium layers with foreign metals it may be advisable to apply thesame through cathode spraying in air whereby, in addition to the interior photo effect, an arrest layer effect occurs, which influences the photoelectric qualities of the, cells in an advantageous direction.
  • an additional mixing. ingredient for the selenium layer, tellurium should talsofbe mentioned, which, as is well known, reduces fatigue phenomena of thephoto-eifect in selenium. i
  • the X-ray sensitive photoelement In contrast tothe known arrest layer cells of selenium, the X-ray sensitive photoelement,accordingto the inventionhasthe advantage or, high ohmic resistance which is of advantage, particularly with regard to the use for the resistance. scanner.
  • a semi-conductive element comprising a radiation sensitive semi-conductive layer ofamorphous selenium having a thickness of about ZOO-microns, said layer having 'beenformed by evaporation in vacuum under avoidance of crystallizationat atemperature below F. to make it sensitive for X-rays, and foreign materials having been added to said amorphous selenium which serve for. sensitivi zing, e. .for reducing the. electric inertia of said. selenium.
  • a photoelectric element comprising a semi-conductive layer consisting of amorphous selenium formed by evaporation'in vacuum under avoidance of crystallization at temperatures below 125 F. and having a thickness of about 200 microns so as to render theresistance of the layer sensitive to X-ray radiation, and large area electrodes in contact with said layer at both sides of said layer, said electrodes consisting of material which does not react with selenium and at least one of said electrodes being penetrable by X-rays.

Description

Nov. 25, 1958 M. PLOKE ET AL 2,862,126
RADIATION SENSITIVE SEMI-CONDUCTIVE LAYER OF AMORPHOUS SELENIUM Filed Aug. 28, 1953 3 Sheets-Sheet 1 Fay] J72 yen to rs flan/red fl elier fiarzzir P101? Nov. 25, 1958 M. PLOKE ET AL 2,862,126
RADIATION SENSITIVE SEMI-CONDUCTIVE LAYER OF AMORPHOUS SELENIUM Filed Aug. 28, 1953 3 Sheets-Sheet 2 I I H" States atent 2,862,126 Patented Nov. 25, 1958 This invention relates to a semi-conductive layer preferably consisting of selenium which has been evaporated in vacuum at a temperature below 125 F. as disclosed in the German Patent 898,641.
Semi-conductive layers consisting of amorphous selenium have hitherto been used for measuring of radiation only. Merely for quantitative indication of the presence of X-rays, semi-conductive layers consisting of amorphous selenium were used which had been made sensitive for X-rays through a prolonged special treatment of the selenium. Said special treatment consisted at least partially in transformation of the amorphous character of the selenium into the crystalline condition, whereby a selenium was obtained which had a low ohmic resistance. Such selenium resistant cells known as Fiirstenau Roentgen radiation intensity measuring devices show too great an inertia, fatigue and ageing in connection with X-rays. The reason'for these phenomena is connected with the crystalline intercalation'of amorphous selenium layers. The required inertia-free receptivity for X-rays, is due to the fact that, the X-ray electric effect, contrary to the radiation-electric effect, depends upon an intra-atomic process for the inception of which the small amountof energy in the radiation is insuficient. Therefore, the radiation sensitivity is, according to earlier perceptions, coupled with the crystalline condition of the matter even if in small traces only.
In order to enable the carrying out of X-ray measuring and X-ray image strengthening free from inertia, fatigue and ageing phenomena; it is suggested, according to the present invention, to employ a semi-conductive layer consisting of amorphous selenium as an X-ray sensitive semi-conductive layer. The formation of crystalline selenium which, according to the above explanations, is the cause of the established inertia and ageing, is avoided when the amorphous selenium layers are evaporated under avoidance of such crystallization, in vacuum upon a support which is maintained at a temperature below 125 F.
It is true that such cold-evaporated layers are extremely insensitive to light as distinguished from layers which have been evaporated on a support having a temperature of, for example, 175 F. Said cold-evaporated layers have the adidtional advantage that their resistance in the dark is one to two units higher than that of hot-evaporated layers, which is of essential importance for their use as a charge feeding layer.
Another not before recognized quality of the amorphous selenium layers in connection with X-rays is that such layers do not show either inertia, fatigue or ageing. It has been established that initiation and termination periods of the change in conductivity at a sudden change in the intensity of the X-ray radiation are of the order of 10 seconds.
In the drawings,
Fig. 1 is a diagram showing the relation between X-ray conductivity and thickness of a selenium layer according to the invention,
Fig. 2 is a perspective view, partly in section, of a longitudinal cell comprising an amorphous selenium layer,
Fig. 3 is a perspective view,-partly in section, of a highohmicX-ray resistance cell according-to the invention,
in relation to the layer thickness.
Fig. 4 shows an X-ray image iconoscope according to the invention,
Fig. 5 shows the invention applied to a conventional orthicon tube,
Fig. 6 shows a cross sectional view of a modified construction and arrangement of the semi-conductive layer and support of the invention, and
Fig; 7 shows a modified arrangement of the construction shown in Fig. 6.
In order to achieve that the X-ray sensitive element which, according to the invention, consists of a layer of amorphous selenium, has a high sensitivity for X-rays, said layer has to be applied in relatively great thickness. The fact is, that experiments have shown that contrary to this, the earlier light sensitive semi-conductive layers of selenium which were applied in a thickness from 1 to 10 microns have very low X-ray sensitivity. Furthermore,'it has been established tht the X-ray conductivity of the amorphous selenium layers is dependent upon the layer thickness to an extremely high degree. Fig. 1 shows the established X-ray conductivity coefiicient am For the investigation a great number of so-called longitudinal cells were produced with amorphous selenium layers of different thickness in accordance with Fig. 2. A glass plate 1 served as carrier for these layers. The amorphous selenium layer 2 is disposed between two evaporated aluminum electrodes 3 and 4. By means of a battery 5 and a galvanometer 10, a circuit isclosed. From the current and the imposed voltage the conductivity change in the cell under X-ray radiation is calculated and therefrom also the X- ray conductivity coefiicient oz in a a 1 82 cm. mr./sec.
(mr.=milli-R6ntgen=dosage unity). The X-ray radiation was obtained as a 60 kv. continuous radiation from an X-ray tube with a' olfram anti-cathode. The X-ray conductivitycoefiicient is thereby related to the received dosage effect in mr. per second. No appreciable dependence .of the X-ray conductivity coeificient upon the hardness of radiation exists between 50 and kv. The dependency of the X-ray conductivity coefficient upon the thickness of the layer runs approximately parallel with the absorbed X-ray radiation in the selenium layer. With the radiation employed, the highest X-ray conductivity coefiicient is obtained at a thickness of the selenium layer of about 300 microns and, therefore, it is not advisable to make the layers thicker than 300 microns.
X-ray sensitive amorphous selenium layers may be used in a variety of apparatus, two embodiments being described below. Fig. 3 shows a perspective view, partly in section, of a high-ohmic X-ray resistance cell accord ing to the invention. This cell is produced by precipitating an amoiphous selenium layer 6 of a thickness of, for example, 200 microns on a metal support plate 7. A metal layer 8 penetra-ble by X-ray radiation is placed on said selenium layer as a counter-electrode. .As electrodes, materials are used which do not react with selenium such as, for example, aluminum, nickel, lampblack, graphite, or carbon. With the two metal electrodes '7 and 8 a circuit is produced over the X-ray sensitive layer and the battery 9, an ammeter 10' being connected in said circuit which shows a current dependent upon the X-ray in tensity with which the cell is irradiated.
Fig. 4 shows an X-ray image iconoscope, the. semiconductive layer of which is formed according to the in vention as an X-ray sensitive amorphous selenium layer,
so that the X-ray image may be scanned in a direct way, i. e, without light transformation. The iconoscope has a bulb 11 of glass'or aluminum which for the purpose of less absorption of the X-ray image is spherical, so that it may be produced with less wall thickness. For the bulb, or the image window, through which the X-ray image penetrates to the amorphous X-ray sensitive selenium layer, preferably a material having a lower absorption coeflicient than glass is used, for example, berryllium glass, or so called Lindernann glass. The screen electrode has a conductive signal plate 12 which is transparent for X-ray radiation. As a signal plate, for example, a thin aluminum sheet may serv e. Said signal plate carries the X-ray sensitive seleniumlayer lfi. ,The 'experiments with X-ray image iconoscopes have shown that a suitable thickness of the amorphous selenium layer 13 is between 50 microns and .300 microns. ,'l ."he signal plate and theiX-ray sensitive selenium layer may also be applied directly to the tube bulb.
Over the operational resistance 14 the signal plate is supplied with a biasing potential. According to the thicknessof the amorphous selenium layer, said biasing potential maybe- 600 v. orlrnore. ln order to interrupt the induced conductivity producedby the scanning ray, it may be advisable toprovide the free surface of the amorphous selenium layer with a mosaic 25 which is impenetrable for the electrons ofthe scanning ray. The load images produced on the free selenium surface through change of resistance in the X-ray sensitive selenium layer are supplied to the image amplifier 16 through the scanning by means of the. electron ray in a known way over the coupling condenser 15. An acceleration electrode 17 suitably comprising a fine mesh net or metal ring is disposed betweenthe signalplate 12 and the scanning aperture 24 of the ray system. In the neck of the glass bulb suitable elements are provided forproducing an electron ray bundle. They consist of a cathode 18 with a heating wire 19, the Wehnelt cylinder 20 and the anode 21. Through the'scanning aperture 24, the electron ray is finely restricted in order to'improve the resolving power of the iconoscope. Bartspfjhe inner surface of the glass bulb are coatedwith .a conductive material so as .to deflect. charges onthe glasswall. Since the X-ray images reach the selenium layer in their natural size, a good dissolution capacity canbe obtained with the iconoscope. Due to the largedeflecting amplitudes, it is necessary to provide for particularly good magnetic screening. 7
Besides the function as an iconoscope with high scanning ray velocity, a function with orthicon electron optics is also possible as shown in Fig. 5. ,In this Figure the X-ray sensitive layer 12 with its support 13 is mounted in the envelope of a conventional orthicon tube 11a which is surrounded by the customary longitudinal focusing coil 23a, while in place of the coil 22 employed in Fig. 4 there is used with the orthicon tube 11a an adjustment coil 22a.
In order to make the selenium more sensitive or, in other words, to decrease its electrical inertia, heavy metals or heavy metal selenium-compounds may be mixed with the selenium such as, for example, lead or leadselenide. Lead selenide is known as a high-ohmic light sensitive substance.
The proportion of said heavymetals in the amorphous selenium layer should be variable from minimum amounts to the stoichiometric relationof the corresponding selenide in order to obtain the most advantageous composition for the responsiveness of the resistance layer to X-rays under all conditions.
Within the framework of the invention also the useability of said foreign ingredients transversely to the maximum extension of the layer is included, for example, so that the side of the layer opposite to the X-rays consists of pure selenium, while the side of said layer facing the X-rays has an increasing proportion of foreign ingredients or selenides 13a, respectively as shown in Fig. 6. .Among the selenides having advantageous photoelectric qualities, silver selenide occupies a prominent position.
With regard to the employment of the cells as resistance scanners, it may also, under certain circumstances, be suitable to enrich the side opposite the X-ray with foreign metals 13b (Fig.7) since. the side facing the scanning ray, that is, the side opposite the X-ray, must have the lower conductivity. Said two considerations may be combined'if the scanning takes place from the side of the X-ray radiation. With regard to the surface activation of selenium layers with foreign metals, it may be advisable to apply thesame through cathode spraying in air whereby, in addition to the interior photo effect, an arrest layer effect occurs, which influences the photoelectric qualities of the, cells in an advantageous direction. As ,an additional mixing. ingredient for the selenium layer, tellurium should talsofbe mentioned, which, as is well known, reduces fatigue phenomena of thephoto-eifect in selenium. i
In contrast tothe known arrest layer cells of selenium, the X-ray sensitive photoelement,accordingto the inventionhasthe advantage or, high ohmic resistance which is of advantage, particularly with regard to the use for the resistance. scanner.
What we claimv is:
.1. A semi-conductive element, comprising a radiation sensitive semi-conductive layer ofamorphous selenium having a thickness of about ZOO-microns, said layer having 'beenformed by evaporation in vacuum under avoidance of crystallizationat atemperature below F. to make it sensitive for X-rays, and foreign materials having been added to said amorphous selenium which serve for. sensitivi zing, e. .for reducing the. electric inertia of said. selenium.
2.,An element as.in claim 1, in which said foreign materials comprise heavy metals.
3. An element as in claim- 2,.in which the proportion of said heavymetalsisvariable from minimum values to thest ichiometric relation ofthe corresponding selenide.
4. An element as in claim 1 in which said foreign materials comprise heavy metal compounds with selenium.
5. An element as in claim 1, in which the proportion of foreign ingredients in theselenium layer is variable transversely to its maximum extension in such a way that the side of the layer opposite to the X-rays consists of pure selenium,.while the side of said layer facing said X-rays-has an increasing proportion of said foreign ingredients.
6. An element as in claim 1, in which said foreign materials comprise selenide of silver.
7. An element as in claim 1, in which the side of the selenium layer opposite to the X-rays is enriched with said foreign materials, while the side of said selenium layer facing the X-rays has less proportion of said foreign materials.
8. An element as in claim 1, including a proportion of tellurium in said selenium layer in order to avoid fatigue phenomena.
9. A photoelectric elementcomprising a semi-conductive layer consisting of amorphous selenium formed by evaporation'in vacuum under avoidance of crystallization at temperatures below 125 F. and having a thickness of about 200 microns so as to render theresistance of the layer sensitive to X-ray radiation, and large area electrodes in contact with said layer at both sides of said layer, said electrodes consisting of material which does not react with selenium and at least one of said electrodes being penetrable by X-rays.
References Cited in the file of this patent UNITED STATES PATENTS 1,491,040 Hart Apr. 22, 1924 2,010,712 Coolidge Aug. 6, 1935 2,569,872 Skehan et al. Oct. 2, 1951 2,608,611 Shiver Aug. 26, 1952 2,654,853 Weimer Qct. 6,1953

Claims (1)

1. A SEMI-CONDUCTIVE ELEMENT, COMPRISING A RADIATION SENSITIVE SEMI-CONDUCTIVE LAYER OF AMORPHOUS SELENIUM HAVING A THICKNESS OF ABOUT 200 MICRONS, SAID LAYER HAVING BEEN FORMED BY EVAPORATION IN VACUUM UNDR AVOIDANCE OF CRYSTALLIZATION AT A TEMPERATURE BELOW 125*F. TO MAKE IT SENSITIVE FOR X-RAYS, AND FOREIGN MATERIALS HAVING BEEN ADDED TO SAID AMORPHOUS SELENIUM WHICH SERVE FOR SENSITIVIZING, I. E. FOR REDUCING THE ELECTRIC INERTIA OF SAID SELENIUM.
US377214A 1953-08-28 1953-08-28 Radiation sensitive semi-conductive layer of amorphous selenium Expired - Lifetime US2862126A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB22985/53A GB748302A (en) 1953-08-28 1953-08-20 Improvements in or relating to x-ray sensitive elements
US377214A US2862126A (en) 1953-08-28 1953-08-28 Radiation sensitive semi-conductive layer of amorphous selenium

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US377214A US2862126A (en) 1953-08-28 1953-08-28 Radiation sensitive semi-conductive layer of amorphous selenium

Publications (1)

Publication Number Publication Date
US2862126A true US2862126A (en) 1958-11-25

Family

ID=23488214

Family Applications (1)

Application Number Title Priority Date Filing Date
US377214A Expired - Lifetime US2862126A (en) 1953-08-28 1953-08-28 Radiation sensitive semi-conductive layer of amorphous selenium

Country Status (2)

Country Link
US (1) US2862126A (en)
GB (1) GB748302A (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3004101A (en) * 1956-04-09 1961-10-10 Gen Electric Color radiography
US3111601A (en) * 1960-05-18 1963-11-19 Singer Inc H R B Selenium storage tube
US3225240A (en) * 1962-09-24 1965-12-21 Gen Electric Image tube having external semiconductive layer on target of wires in glass matrix
US3300669A (en) * 1963-09-16 1967-01-24 Machlett Lab Inc X-ray vidicon having a target and window assembly with improved thermal conductivity
US3466388A (en) * 1961-12-27 1969-09-09 Univ Ohio State Res Found X-ray television inspection system with selenium camera tube target
US3963633A (en) * 1971-12-06 1976-06-15 Owens-Illinois, Inc. Gas discharge device dielectric containing selenium, tellurium and/or polonium
US4025793A (en) * 1975-10-20 1977-05-24 Santa Barbara Research Center Radiation detector with improved electrical interconnections
US4317367A (en) * 1977-03-18 1982-03-02 Milton Schonberger Fever thermometer, or the like sensor
US4589006A (en) * 1982-08-23 1986-05-13 The United States Of America As Represented By The United States Department Of Energy Germanium detector passivated with hydrogenated amorphous germanium
US4731560A (en) * 1970-08-06 1988-03-15 Owens-Illinois Television Products, Inc. Multiple gaseous discharge display/memory panel having improved operating life
US4794308A (en) * 1970-08-06 1988-12-27 Owens-Illinois Television Products Inc. Multiple gaseous discharge display/memory panel having improved operating life

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2601499B1 (en) * 1986-07-08 1988-09-30 Thomson Csf MEMORY PHOTOCONDUCTOR IMAGE DETECTOR

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1491040A (en) * 1921-03-24 1924-04-22 Hart Russell Process of manufacturing selenium cells for photo-electric work and crystal radiodetectors
US2010712A (en) * 1930-09-23 1935-08-06 Gen Electric Cathode ray tube
US2569872A (en) * 1949-12-24 1951-10-02 Machlett Lab Inc Electron discharge tube
US2608611A (en) * 1949-08-17 1952-08-26 Bell Telephone Labor Inc Selenium rectifier including tellurium and method of making it
US2654853A (en) * 1949-02-28 1953-10-06 Rca Corp Photoelectric apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1491040A (en) * 1921-03-24 1924-04-22 Hart Russell Process of manufacturing selenium cells for photo-electric work and crystal radiodetectors
US2010712A (en) * 1930-09-23 1935-08-06 Gen Electric Cathode ray tube
US2654853A (en) * 1949-02-28 1953-10-06 Rca Corp Photoelectric apparatus
US2608611A (en) * 1949-08-17 1952-08-26 Bell Telephone Labor Inc Selenium rectifier including tellurium and method of making it
US2569872A (en) * 1949-12-24 1951-10-02 Machlett Lab Inc Electron discharge tube

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3004101A (en) * 1956-04-09 1961-10-10 Gen Electric Color radiography
US3111601A (en) * 1960-05-18 1963-11-19 Singer Inc H R B Selenium storage tube
US3466388A (en) * 1961-12-27 1969-09-09 Univ Ohio State Res Found X-ray television inspection system with selenium camera tube target
US3225240A (en) * 1962-09-24 1965-12-21 Gen Electric Image tube having external semiconductive layer on target of wires in glass matrix
US3300669A (en) * 1963-09-16 1967-01-24 Machlett Lab Inc X-ray vidicon having a target and window assembly with improved thermal conductivity
US4731560A (en) * 1970-08-06 1988-03-15 Owens-Illinois Television Products, Inc. Multiple gaseous discharge display/memory panel having improved operating life
US4794308A (en) * 1970-08-06 1988-12-27 Owens-Illinois Television Products Inc. Multiple gaseous discharge display/memory panel having improved operating life
US3963633A (en) * 1971-12-06 1976-06-15 Owens-Illinois, Inc. Gas discharge device dielectric containing selenium, tellurium and/or polonium
US4025793A (en) * 1975-10-20 1977-05-24 Santa Barbara Research Center Radiation detector with improved electrical interconnections
US4317367A (en) * 1977-03-18 1982-03-02 Milton Schonberger Fever thermometer, or the like sensor
US4589006A (en) * 1982-08-23 1986-05-13 The United States Of America As Represented By The United States Department Of Energy Germanium detector passivated with hydrogenated amorphous germanium

Also Published As

Publication number Publication date
GB748302A (en) 1956-04-25

Similar Documents

Publication Publication Date Title
US3546515A (en) Photocathode control of electron flow through lead monoxide,bombardment-induced conductivity layer
US2862126A (en) Radiation sensitive semi-conductive layer of amorphous selenium
US3350595A (en) Low dark current photoconductive device
DE821092C (en) Photosensitive element
US3995159A (en) Thermal imaging systems
US2890359A (en) Camera tube
EP0005543A1 (en) Photosensor
US2177736A (en) Television transmitting apparatus
US3289024A (en) Photo-sensitive device including layers of different conductivity types
US3693018A (en) X-ray image intensifier tubes having the photo-cathode formed directly on the pick-up screen
US3405298A (en) Photoconductive device having a target including a selenium blocking layer
US5365056A (en) X-ray image intensifier having an image sensor with amorphous semiconductor material layer
US3711719A (en) Storage amplifier screen
US2730638A (en) Photoconductive electrode
US3571646A (en) Photoconductive target with n-type layer of cadmium selenide including cadmium chloride and cuprous chloride
US2212923A (en) Picture transmitter
US3310700A (en) Photoconductive device incorporating stabilizing layers on the face of the selenium layer
US3123737A (en) schneeberger
US4025814A (en) Television camera tube having channeled photosensitive target spaced from signal electrode
US3268764A (en) Radiation sensitive device
US3082340A (en) Radiation sensitive device
US4068253A (en) Photoconductor element and method of making the element
CA1060568A (en) Photoelectric device
US3252030A (en) Photoelectric camera tube with transistor-type photoanode
US3783324A (en) Photosensitive charge storage electrode having a selectively conducting protective layer of matching valence band on its surface