Abstract: An electron source includes a back contact surface having a means for attaching a power source to the back contact surface. The electron source also includes a layer comprising platinum in direct contact with the back contact surface, a composite layer of single-walled carbon nanotubes embedded in platinum in direct contact with the layer comprising platinum. The electron source also includes a nanocrystalline diamond layer in direct contact with the composite layer. The nanocrystalline diamond layer is doped with boron. A portion of the back contact surface is removed to reveal the underlying platinum. The electron source is contained in an evacuable container.

Abstract: An oxynitride fluorescent material includes a JEM phase as a mother crystal and a luminescence center element Ce. The oxynitride fluorescent material has a fluorescence spectrum with a maximum emission wavelength of 420 nm to 500 nm inclusive and an excitation spectrum with a maximum excitation wavelength of 250 nm to 400 nm inclusive.

Abstract: A plasma display panel includes: pairs of electrodes having first electrode and second electrode which are arranged in parallel with each other; first substrate having dielectric layer formed so that the dielectric layer can cover the pairs of electrodes; and second substrate having third electrode which is arranged crossing the pairs of electrodes, and the plasma display panel further includes: floating electrodes, protruding onto a discharge space provided on dielectric layer at positions respectively corresponding to first electrode and second electrode, wherein floating electrodes are opposed to each other. Due to the above composition, the discharge starting voltage is reduced and the drive voltage is decreased. Accordingly, the light emitting efficiency is enhanced.

Abstract: The invention relates to charged particle beam accelerators, in particular electron beam accelerators, and can be used for physics, chemistry and medicine. The inventive charged particle beam accelerator comprises a metallic shell fitted with a dielectric material layer arranged therein, and a vacuum channel for electron transit embodied along the central symmetry axis of said metallic shell. In addition, the metallic shell is fitted with a ferroelectric material layer arranged therein. Said ferroelectric material layer can be arranged between the metallic shell and the dielectric material layer or in said dielectric material layer. The invention provides an object with a very important property, i.e. said property makes it possible to control the accelerator parameters and regulate the phase balance of the charged particle beam and the wave that accelerates the particles.

Abstract: Disclosed is a method of forming a reflection film and a heat absorbing film on the inner surface of a panel of a cathode ray tube by using a vacuum vapor-deposition process. In the case of using aluminum as the material for the reflection film, chromium is used as the material for the heat absorbing film. Chromium has a boiling point under a vacuum pressure at the time of vapor-deposition, which is higher than that of aluminum. The mixture of aluminum and chromium is supplied to a heater portion, and is heated and vaporized by the heater portion to be deposited on the inner surface of the panel. In this deposition, aluminum is first vapor-deposited and then chromium is vapor-deposited. Accordingly, the two kinds of films are formed in one vapor-deposition step.

Abstract: There are provided a composition for forming a conductive layer comprising 0.01˜0.1% by weight of a conductive black pigment, 0.05˜10% by weight of a binder,0.01˜50% by weight of a conductive agent, and the remaining amount of a solvent on the basis of the total weight of the composition, and a cathode ray tube (CRT) having the conductive layer formed by coating the composition on the outer surface of a panel, drying and heating the same, and a protective layer formed on the conductive layer. The conductive layer formed using the composition has excellent conductivity, contrast characteristics and film properties. Also, a clean color purity and high-quality body color are attained.

Abstract: A method for fabricating an electron multiplier is provided. The method consists of depositing a random channel layer on a substrate such that the random channel layer is capable of producing a cascade secondary electron emission in response to an incident electron in the presence of an electric field.

Abstract: In order to increase the sensitivity of an image intensifier tube, the efficiency with which an electron image is formed from radiation of a first wavelength is increased. Radiation of the first wavelength is converted into radiation of a second wavelength by means of a conversion screen provided with a scintillation layer, and radiation of the second wavelength releases electrons from a photocathode which is sensitive to the second wavelength. Loss of radiation of a second wavelength, incurred because a part of this radiation does not reach the photocathode, is reduced. Radiation of the second wavelength which is not emitted in the direction of the photocathode is recaptured by providing the conversion screen with a metallic reflecting intermediate layer.

Abstract: A camera device having favorable multiplication characteristics (quantum efficiency) as well as improved sensitivity in a visible light region (especially the region on the red side) and a method of manufacturing the same are provided. The camera device includes a hole injection stop layer, a first photoelectric converting layer including selenium, a second photoelectric converting layer having spectral sensitivity characteristics which are different from those of the first photoelectric converting layer, a third photoelectric converting layer including selenium, and an electron injection stop layer. As a result, it is possible to improve multiplication characteristics (quantum efficiency) and to improve the sensitivity in the visible light region (especially the region on the red side) simultaneously.

Abstract: A high resolution infrared scene simulator formed by a novel combination of a photo-cathode, one or more micro-channel plates and a uniquely constructed air-bridge thermal screen. The photo-cathode is used to covert photons into electrons for insertion into the input side of the micro-channel plate. The micro-channel plate is a photo-electric device comprising a parallel array of independent channel, electron multipliers capable of high gain electron amplification. The air-bridge thermal screen comprises numerous thermally isolated thin platelets, bridges or diaphragms whose individual thermal mass and resistance are respectively low and high. Such platelets are thermally isolated and are supported on a structure that is capable of being cooled and electrically conductive.

Abstract: A photoconductive device having a photoconductive layer which includes an amorphous semiconductor layer capable of charge multiplication in at least a part thereof is disclosed. The method of operating such a photoconductive device is also disclosed. By using the avalanche effect of the amorphous semiconductor layer, it is possible to realize a highly sensitive photoconductive device while maintaining low lag property. In one aspect of the present invention, the amorphous semiconductor layer is amorphous Se. In another aspect of the present invention, the amorphous semiconductor layer is composed mainly of tetrahedral elements including at least an element of hydrogen or halogens. When using the amorphous semiconductor layer composed mainly of tetrahedral elements, the charge multiplication effect is produced mainly in the interior of the amorphous semiconductor, and thus it is possible to obtain a thermally stable photoconductive device having a high sensitivity while keeping a good photoresponse.

Abstract: A photoconductive device having a transparent substrate, a transparent conductive film, a photoconductive film and a layer of an insulator provided on at least part of the substrate and of high thermal conductivity, and a method of operating the photoconductive device. Thus, especially, the temperature of a photoconductive film of an imaging device typical of an image pick-up tube or the photoconductive device which may be a one- or a two-dimensional image sensor or a photocell can be controlled precisely and efficiently.

Abstract: An image pick-up tube and a method of fabricating an image pick-up tube and a target section used therewith, in which the target includes at least a conductive film and a photoconductive film on a substrate for photo-electric conversion, and a signal from the target section is read by an electron beam scanning system. At least a part of the surface area outside the effective scanning region of the electron beam scanning side of the target section is formed of a secondary electron emission dampening layer.

Abstract: A target of an image pickup tube is formed by laminating at least a transparent conductive film, an amorphous layer consisting essentially of silicon, and an amorphous layer consisting essentially of selenium in the above order on a light-transmitting substrate.

Abstract: A target of an image pickup tube, having a transparent substrate, a transparent conductive film, a p-type photoconductive film made mainly from amorphous Se, and an n-type conductive film capable of forming a rectifying contact at the interface with the p-type photoconductive film, using the rectifying contact as a reverse bias, characterized in that the p-type photoconductive film containing at least a region having more than 35%, and to 60% by weight of Te in the film thickness direction, and at least a region containing 0.005 to 5% by weight of at least a material capable of forming shallow levels in the amorphous Se in the film thickness direction, has good after-image characteristics even if operated at a high temperature.

Abstract: There is disclosed an image pick-up tube target comprising an N-type conductive film formed on a transparent substrate, and a P-type photoconductive film in rectifying contact with the N-type conductive film and comprising a first layer containing As and Se, the average concentration of As in the first layer being below 8% by weight, a second layer containing As and Se, a third layer containing As and Se, the concentration of As being in the range of 8 to 20% by weight and thickness of the third layer being in the range of 5 to 50% of the total thickness of the P-type photoconductive film, in the order named, and a beam landing layer.

Abstract: An imaging plate structure having a first conductive layer, a first insulative layer, a photoconductive layer, a second insulative layer, and a second conductive layer. The first insulative layer is integrally affixed to the side of the first conductive layer. The photoconductive layer is integrally affixed to the other side of the first insulative layer. The second insulative layer is integrally affixed to the other side of the photoconductive layer. The second conductive layer is integrally affixed to the other side of the second insulative layer. Both the first and the second insulative layers have a thickness suitable for preventing charge tunnelling therethrough. These first and second insulative layers are made of a true insulator material. The photoconductive layer is comprised of a photoconductor that is responsive to radiation of known energy. The first conductive layer and the first insulative layer are transmissive with respect to the radiation acting on the imaging plate.

Abstract: In one example of construction, a high-performance photocathode has the following structure:a transparent layer formed of P.sup.+ type semiconductor material having a forbidden band of sufficient width to ensure that this layer is transparent to the photons of the light to be detected;an absorption layer constituted by ten first sublayers formed of P.sup.

Abstract: An image pick-up tube target comprising an N-type conductive film formed on a transparent substrate, and P-type photoconductive film in rectifying contact with the N-type conductive film and comprising a first layer containing As, fluoride and Se, a second layer containing As, Te and Se, a portion of said second layer containing fluoride, a third layer containing As and Se, the composition of the third layer being different along the direction of thickness thereof, a fourth layer containing As and Se, wherein the concentration of As in the second layer varies continuously along the direction of thickness thereof, and in the second layer the minimum As concentration is located on the first layer side of the second layer and the maximum As concentration is located on the third layer side of the second layer.

Abstract: The present invention is a photoconductive member which includes a layer of amorphous semiconductor, adjacent to a multilayered amorphous semiconductor material, the composite material sandwiched between two blocking layers. The entire structure is supported by a layer of metal or glass depending on whether the photoconductive member is used in electrophotography or in an image pickup tube.

Abstract: A semi-conductor device comprising a lamination of a photoconductive layer, a charge-retaining layer and a display layer, provided between electroconductive films, and an electronic apparatus utilizing said semi-conductor device are provided.

Abstract: A flat gas discharge display includes a gas-filled envelope having mutually parallel front and rear wall plates disposed one behind the other as seen in a given viewing direction, at least one relatively large area cathode disposed on the front side of the rear wall plate, a cathodoluminescent layer and an anode disposed on the rear side of the front wall plate, a control unit disposed between the wall plates including front, central and rear grid electrodes each formed of a group of mutually parallel strip conductors, the strip conductors of the central grid electrode being column conductors, the strip conductors of the rear grid electrode being row conductors forming an orthogonal matrix together with the column conductors, and the strip conductors of the front grid electrode being tetrode conductors extended parallel to the row conductors and crossing the column conductors at given locations, the control unit being perforated with canals at the given locations where the tetrode conductors and column conduc

Abstract: A high velocity electron beam scanning negatively charge biased image pickup tube has a target which includes at least a transparent conductive layer, a photoconductor layer and a layer for secondary electron emission on a light-transmissive insulating substrate, and in which the transparent conductive layer is arranged on a light incidence side, the photoconductor layer being made of amorphous silicon.

Abstract: A photosensor including a transparent electrode for transmitting incident light and a photoconductive layer receiving light from the transparent electrode for performing photoelectric conversion, is disclosed in which the photoconductive layer is made of amorphous silicon, the amorphous silicon contains 5 to 30 atomic percent hydrogen and is doped with at least one selected from elements belonging to the groups II and III in such a manner that a region remote from the transparent electrode is higher in the concentration of the selected element than another region proximate to the transparent electrode, and a voltage is applied across the photoconductive layer so that a surface of the photoconductive layer facing the transparent electrode is at a positive potential with respect to another surface of the photoconductive layer opposite to the surface facing the transparent electrode.

Abstract: A photoconductive target of an image pickup tube consists of a transparent substrate, a transparent conductor formed thereon, a photoconductive layer, containing Cd, Te and Se and formed on the conductive layer, and a high resistance layer formed on the photoconductive layer. The Molar ratios of Cd, Te and Se contained in the photoconductive layer satisfy a general formula CdTe.sub.1-x Se.sub.x where x falls within the range between 0.3 and 0.5.

Abstract: Disclosed is a photoconductive target of an image pickup tube having a transparent substrate, a transparent conductive layer formed on the transparent substrate, a photoconductive layer formed on the transparent conductive layer and containing cadmium, tellurium and selenium as major components, and a high resistance layer formed on the photoconductive layer. The film thickness of the photoconductive layer is more than 1,000 .ANG. and less than 10,000 .ANG. and the film thickness of the high resistance layer falls within the range between 2 and 10 .mu.m.

Abstract: An image pickup tube target includes a Se-As-Te photoconductive layer whose arsenic concentration changes in a direction of thickness of the Se-As-Te photoconductive layer, a carrier extraction layer having a high arsenic concentration and being contiguous to the Se-As-Te photoconductive layer, a capacitive layer having a low arsenic concentration and being contiguous to the carrier extraction layer, a doped layer obtained by doping In.sub.2 O.sub.3, MoO.sub.2 or a mixture thereof in an interface between the carrier extraction layer and the capacitive layer.

Abstract: A multi-layered photoconductive material which comprises first layers containing at least one VIb chalcogen element chosen from S, Se and Te and second layers containing at least one IIb element chosen from Zn, Cd and Hg and acting as electric potential barriers, said first layers and said second layers being alternatively arranged and the total number of said first layers and said second layers being not less than 5 and has a high response speed and an excellent sensitivity to long wavelength light with a great dark resistance.

Abstract: An image pickup tube comprising a target composed of a light-transmissible plate, a transparent electrode provided on said light-transmissible plate and a photoconductor made of hydrogen-containing amorphous silicon provided on said transparent electrode; an electron beam generator; and a mesh electrode near the aforesaid target, at least the surface of said mesh electrode being made of at least one member selected from the group consisting of Be, B, C, Mg, Al and Si, has high resolution with greatly improved life characteristics.

Abstract: A photoconductive image pick-up tube target comprises a transparent substrate, an N-type conductive film formed on the transparent substrate, and a P-type photoconductive film in rectifying contact with the N-type conductive film and containing Se, As and Te as sensitizer. The P-type photoconductive film includes a first layer contiguous to the N-type conductive film and containing 94.+-.1% by weight of Se and 6.+-.0.5% by weight of As, a second layer formed on the first layer and containing 64.+-.4% by weight of Se, 3.+-.0.5% by weight of As, and 33.+-.2% by weight of Te, a third layer formed on the second layer and containing Se and As, and a fluoride doped region extending over the first layer and a front half layer of the second layer and having a fluoride concentration of 0.1 to 3.0% by weight. The third layer has an As concentration which has a peak of 28.+-.1% by weight at a site contiguous to a rear half layer of the second layer and reduces gradually.

Abstract: Disclosed is a photoelectric device having at least a signal electrode, and an amorphous photoconductor layer whose principal constituent is silicon and which contains hydrogen as an indispensable constituent element, the amorphous photoconductor layer being disposed in adjacency to the signal electrode, characterized by comprising a thin layer interposed between the signal electrode and the amorphous photoconductor layer, the thin layer being made of an inorganic material whose principal constituent is at least one compound selected from the group consisting of oxides of at least one element selected from the group that consists of Si, Ti, Al, Mg, Ba, Ta, Bi, V, Ni, Th, Fe, La, Be, Sc and Co, nitrides of at least one element selected from the group that consists of Ga, Si, Mg, Te, Hf, Zr, Nb and B, and halides of at least one element selected from the group that consists of Na, Mg, Li, Ba, Ca and K.

Abstract: An image pickup tube of high velocity electron beam scanning and negatively charging system having a target including, on a transparent substrate, at least a transparent conductive film, a photoconductive layer, a layer for emitting secondary electrons, and stripe electrodes. The transparent substrate may be made of amorphous silicon.

Abstract: An electron emitting device including an active semiconductor layer having a surface from which electrons are emitted. The layer is doped with impurity atoms at a density which decreases with distance from the surface.

Abstract: A photoconductive member comprises a support for a photoconductive member, a first amorphous layer having a layer constitution comprising a first layer region comprising an amorphous material containing silicon atoms and germanium atoms and a second layer region comprising an amorphous material containing silicon atoms and exhibiting photoconductivity, said first and second layer regions being provided successively from the side of said support; and a second amorphous layer comprising an amorphous material containing silicon atoms and carbon atoms.

Abstract: A television camera tube using a target comprising an electrically-conductive support, a blocking layer composed of a n-type amorphous silicon semiconductor, provided on the electrically-conductive support, and a light-sensitive layer composed of amorphous silicon provided on the blocking layer.

Abstract: A radiation-sensitive tube is described having a target comprising (1) an electrically conductive support, (2) at least one layer composed of insulative an amorphous silicon represented by the formula Si.sub.1-x N.sub.x wherein 1>x, y and z.gtoreq.0 and 1>x+y+z>0 and (3) a photoconductive layer composed of amorphous silicon.

Abstract: A photoconductive film comprising a photo-conductive layer which is mainly made of selenium and a region added with tellurium in a direction of the thickness of the layer, wherein at least either one of a portion in a direction of hole flow of said region added with tellurium and a portion in the hole flow of another region which is located adjacent to said region added with tellurium is doped with at least one member selected from the group consisting of an oxide, a fluoride and elements which belong to the group II, III and VII, which are capable of forming a negative space charge in selenium, at a concentration in a range of 10 ppm to 1% by weight on an average. Typical examples of such oxide, fluoride and element include CuO, In.sub.2 O.sub.3, SeO.sub.2, V.sub.2 O.sub.5, MoO.sub.3, WO.sub.3, GaF.sub.2 InF.sub.3, Zn, Ga, In, Cl, I, Br and the like. The after image characteristic ascribable to incident light of high intensity can be significantly improved.

Abstract: Disclosed is a light sensitive screen including at least a light-transmitting conductive film and a photoconductive layer, the light-transmitting conductive film being arranged on a side of incidence of light, characterized in that the photoconductive layer is constructed of a single layer or a plurality of layers of one or more photoconductive substances, at least one of such photoconductive substance layers being formed of an amorphous silicon material which contains at least 5 atomic-% to 30 atomic-% of hydrogen, whose optical forbidden band gap is 1.65 eV to 2.25 eV and whose peak component in an infrared absorption spectrum at a wave number of 2,100 cm.sup.-1 is greater than that at a wave number of 2,000 cm.sup.-1. Various characteristics of an imaging device provided with the light sensitive screen, such as dark current, lag and after image characteristics, are improved.

Abstract: In a step for bonding a color filter to a solid-state image sensor so as to provide a color-sensitive image sensor (to be referred to as "a color-image sensor" in this specification), a method for bonding the color filter to the image sensor with an adhesive which is curable by ultraviolet radiation and also the constructions of color filters and image sensors which can facilitate the bonding step.

Abstract: There is disclosed a photoelectric conversion device comprising a transparent substrate; a transparent conductive film formed on said substrate; a photoconductive layer formed of hydrogenated amorphous silicon as an indispensable component and deposited on said transparent conductive film; and a chalcogen glass film formed on said photoconductive layer, wherein said chalcogen glass film includes at least a chalcogen glass layer formed in an atmosphere of inert gas kept at 1.5.times.10.sup.-2 to 1.5.times.10.sup.-1 Torr. As chalcogen glass is preferably used Sb.sub.2 S.sub.3, As.sub.2 S.sub.3, As.sub.2 Se.sub.3 or Sb.sub.2 Se.sub.3. The chalcogen glass film may be a composite film consisting of plural component layers. This invention is very useful to reduce dark current in an image pickup tube and to prevent image inversion in the image pickup tube.

Abstract: In the faceplate structure of image pickup tube having an organic coat, an inorganic transparent conductive film and an inorganic photoconductive film sequentially laminated on the central part of a transparent glass base, the inorganic transparent conductive film and the inorganic photoconductive film are formed so that they are non-porous in at least part of their respective sub-layers in the direction of lamination. Further, the transparent conductive film and the photoconductive film have a larger area than that of the organic coat so that they will completely cover the organic coat.

Abstract: In a step for bonding a color filter to a solid-state color-image sensor chip with an adhesive which is curable not only by light or more particularly ultraviolet-ray irradiation but also by heating, pre-curing or partial curing is effected by irradiating light rays after the color filter and the chip has been pressed against each other and correctly aligned with each other in a bonding device and then the chip with the partially-bonded color filter is removed from the bonding device and complete curing of the adhesive is accomplished by heating. According to one embodiment of the present invention the bonding step is carried out in an atmosphere containing the oxygen so that the adhesive which has been squeezed out from the space between the color filter and the clip may be prevented from being cured and subsequently removed in a simple manner.

Abstract: A camera tube target (9) which is to be scanned on one side by an electron beam (20), comprises a selenium-containing vitreous layer (21) also containing tellurium and arsenic. In order to improve various target characteristics and properties in accordance with the invention, the concentration of at least one of the elements tellurium and arsenic in a first sub-layer (25) of the selenium-containing layer (21), on the side to be scanned, increases toward the side to be scanned to a value at which the sum of the concentrations of tellurium and arsenic is at most 30 at. %. The arsenic concentration everywhere in the layer (21) exceeds 1.5 at. %. In a second sub-layer (26) adjoining the first sub-layer (25) the concentration of at least one of the elements arsenic and tellurium is smaller than its concentration an adjoining third sub-layer (27). A fourth sub-layer (28) may also be present between the third sub-layer (27) and the signal electrode (22).

Abstract: A photoelectric transfer device in which an electroconductive layer is formed on a surface of an oxide substrate comprising lead component at a ratio of 30-99.5 mol % as PbO and chromium component at a ratio of 0.5-70 mol %, preferably at a ratio of 60-90 mol % as PbO and a chromium component at a ratio of 10-40 mol %.

Abstract: A method of manufacturing a target of an image pickup tube comprising the steps of: forming a plurality of groups of transparent conductive signal electrodes on a transparent insulating base plate; forming a first layer on at least a portion constituting an image area of the image pickup tube, said first layer being substantially insoluble in etching liquid used for etching an insulating layer to constitute an intermediate layer insulator in a double layered interconnection structure; forming, after formation of said first layer, an insulating layer to constitute said intermediate-layer insulator; removing a predetermined portion of said insulating layer, removing said first layer together with said insulating layer located thereon; forming bus bars; and forming a photoconductive layer on said plurality of groups of the transparent conductive signal electrodes.This invention provides an excellent method for mass production.

Abstract: A photoconductive target having an electrode and a P-type conductive layer mainly made of Se and making rectifying contact at an interface with the electrode, with at least Te being doped in a portion of the P-type conductive layer. At least one metal fluoride forming shallow levels is doped in the region where the signal current is generated for the most part of the P-type conductive layer with an average concentration of not less than 50 ppm and not more than 5% by weight. The metal fluoride is preferably at least one selected from the group consisting of LiF, NaF, MgF.sub.2, CaF.sub.2, BaF.sub.2, AlF.sub.3, CrF.sub.3, MnF.sub.2, CoF.sub.2, PbF.sub.2, CeF.sub.3 and TlF. The high light sticking of the photoconductive target can thus be considerably reduced.

Abstract: A camera tube having an electron source and a target to be scanned on one side by an electron beam emanating from said source. Radiation forming the image to be detected is incident on the other side of the target. The target comprises a signal electrode and a selenium-containing vitreous layer containing arsenic. The arsenic concentration in the selenium-containing layer increases continuously from the radiation-receiving side of the layer to the side which is scanned by the electron beam. The signal electrode is on the radiation-receiving side of the layer and thus on the radiation-receiving side of the target.

Abstract: A photoelectric device comprises a signal electrode, a layer of amorphous photoconductor containing 50 atomic percent or more of selenium and an N-type semiconductor layer made of a material selected from the group consisting of oxygen depletion type cerium oxide and oxygen depletion type lead oxide and disposed therebetween, which has a thickness greater than 8 nm and up to and including 500 nm and a Fermi level located within an energy range of 0.2 to 0.8 eV from the bottom of a conduction band.

Abstract: In a photosensor having at least a light-transmitting conductive layer which is arranged on the side of light incidence, and a photoconductive layer in which charges are stored in correspondence with the light incidence; a photosensor characterized in that at least a region of said photoconductive layer for storing the charges is made of an amorphous material which contains hydrogen and silicon as indispensable constituent elements thereof, in which the silicon amounts to at least 50 atomic % and the hydrogen amounts to at least 10 atomic % and at most 50 atomic %, and whose resistivity is not lower than 10.sup.10 .OMEGA..multidot.cm.

Abstract: A camera tube having an electron source and a target to be scanned on one side by an electron beam emanating from the source. The target comprises a signal electrode and a selenium-containing vitreous layer containing tellurium, in a concentration which varies in the direction of the thickness of the selenium-containing layer, and arsenic. The selenium-containing layer is on the side of the target to be scanned by the electron beam, the signal electrode is on the side of the target to receive radiation. The tellurium concentration in the selenium-containing layer increases from the radiation-receiving side of the layer to the side which is scanned by the electron beam in such manner that over a distance of at most 0.3 microns from the radiation-receiving side, the concentration reaches a value of at least 41/2 atomic % and the arsenic concentration uniformly exceeds 11/2 atomic %.