# US 4,377,628 A · Electrophotographic member with .alpha.-Si and H > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,377,628 A - Document ID: US4377628A - Status: Granted - Kind: A - Application number: 06/257,346 - Filed: 1981-04-24 - Granted: 1983-03-22 - Earliest claimed: 1980-04-25 - Assignees: Hitachi, Ltd. - Inventors: Sachio Ishioka; Eiichi Maruyama; Yoshinori Imamura; Hirokazu Matsubara; Shinkichi Horigome - Web page: https://patentgrep.com/patent/US4377628A ## CPC - G03F 7/70216: {Mask projection systems} - G03F 7/707: {Chucks, e.g. chucking or un-chucking operations or structural details} - G03G 5/08221: {comprising one or two silicon based layers} - G03G 5/08235: {comprising three or four silicon-based layers} - G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G) - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract Disclosed is an electrophotographic member having an amorphous-silicon photoconductive layer, wherein the distance between a portion in which light illuminating the photoconductor is absorbed therein until its intensity decreases to 1% of that at incidence and the interface of the photoconductor opposite to the light incidence side thereof is at most 5 .mu.m, whereby the residual potential of the photoconductive layer can be reduced. That part of the photoconductive layer constituting the electrophotographic member which is at least 10 nm thick inwardly of the photoconductive layer from the surface thereof to store charges is made of amorphous silicon which has an optical forbidden band gap of at least 1.6 eV and a resistivity of at least 10.sup.10 .OMEGA..multidot.cm. Further, within such photoconductive layer, a region of amorphous silicon which has an optical forbidden band gap smaller than that of the amorphous silicon forming the surface part is disposed at a thickness of at least 10 nm. By forming the region of the narrower optical forbidden band gap within the photoconductive layer in this manner, the sensitivity of the photoconductive layer to light of longer wavelengths can be enhanced. ## Claims ### Claim 1 In an electrophotographic member having at least a support and a photoconductive layer of amorphous silicon containing hydrogen carried by said support, said support being made of a conductive material or an insulating material having a layer of a conductive material thereon, the improvement comprising that said photoconductive layer of an amorphous silicon containing hydrogen has at least 50 atomic % amorphous silicon and said hydrogen amounts to at least 1 atomic % and at most 50 atomic %, and that the distance between the region at which the intensity of light illuminating said photoconductive layer on the light incident side thereof is reduced by absorption therein to 1% of that at incidence and the surface of said photoconductive layer opposite to said light incident side thereof is at most 5 .mu.m. ### Claim 2 (depends on 1) An electrophotographic member according to claim 1, wherein a part which is at least 10 nm thick inwardly of said photoconductive layer from a surface thereof is made of amorphous silicon which has an optical forbidden band gap of at least 1.6 eV and a resistivity of at least 10.sup.10 .OMEGA..multidot.cm. ### Claim 3 (depends on 2) An electrophotographic member according to claim 2, wherein said photoconductive layer of an amorphous silicon containing hydrogen includes a sublayer disposed beyond a surface part of said photoconductive layer, said sublayer having an optical forbidden band gap that is smaller than that of said amorphous silicon forming said surface part, and said sublayer having a thickness of at least 10 nm. ### Claim 4 (depends on 3) An electrophotographic member according to claim 3, wherein an interface region of said photoconductive layer opposite to said surface thereof is made of amorphous silicon which has an optical forbidden band gap of at least 1.6 eV and a resistivity of at least 10.sup.10 .OMEGA..multidot.cm, said optical forbidden band gap of said amorphous silicon of said interface region being larger than that of the amorphous silicon forming the sublayer of said photoconductive layer. ### Claim 5 (depends on 3, 4) An electrophotographic member according to any one of claims 3 and 4, wherein an end face of the sublayer of said photoconductive layer of smaller optical forbidden band gap is at most 5 .mu.m distant from said surface opposite to said light incident side of said photoconductive layer. ### Claim 6 (depends on 1, 2, 3, 4) An electrophotographic member according to any one of claims 1 to 4, wherein said photoconductive layer of amorphous silicon containing hydrogen is formed by reactive sputtering in an atmosphere containing hydrogen. ### Claim 7 (depends on 1, 2, 3, 4) An electrophotographic member according to any one of claims 1 to 4, wherein a part of said amorphous silicon is substituted by at least one element selected from the group consisting of germanium and carbon, wherein the quantity of the substitution by said at least one element is within 30 atomic %. ### Claim 8 In an electrophotographic system having at least an electrophotographic member which has a support and a photoconductive layer of amorphous silicon containing hydrogen carried by said support, said support being made of a conductive material or an insulating material having a layer of a conductive material thereon, and a light source which illuminates the electrophotographic member; the improvement comprising that said photoconductive layer of an amorphous silicon containing hydrogen has at least 50 atomic % amorphous silicon and said hydrogen amounts to at least 1 atomic % and at most 50 atomic %, and that the distance between a region at which the intensity of light illuminating said photoconductive layer on the light incident side thereof is reduced by absorption therein to 1% of that at incidence and the surface of said photoconductive layer opposite to said light incident side thereof is at most 5 .mu.m. ### Claim 9 (depends on 8) An electrophotographic system according to claim 8, wherein a surface part which is at least 10 nm thick inwardly of said photoconductive layer of an amorphous silicon containing hydrogen from a surface thereof is made of amorphous silicon which has an optical forbidden gap of at least 1.6 eV and a resistivity of at least 10.sup.10 .OMEGA..multidot.cm, and wherein a sublayer of said photoconductive layer is disposed beyond the surface part of said photoconductive layer, said sublayer having an optical forbidden band gap that is smaller than that of said amorphous silicon forming said surface part and having a thickness of at least 10 nm. ### Claim 10 (depends on 8, 9) An electrophotographic system according to any one of claims 8 and 9, wherein a part of said amorphous silicon is substituted by at least one element selected from the group consisting of germanium and carbon, wherein the quantity of the substitution by said at least one element is within 30 atomic %. ### Claim 11 (depends on 1, 2, 3, 4) An electrophotographic member according to any one of claims 1 to 4, further including a blocking layer at the side of said photoconductive layer adjacent said support for suppressing the injection of excess carriers from said support side. ### Claim 12 (depends on 11) An electrophotographic member according to claim 11, wherein said blocking layer at the side of the photoconductive layer adjacent said support is made of a material selected from the group consisting of SiO, SiO.sub.2, CeO.sub.2, Ta.sub.2 O, Al.sub.2 O.sub.3, V.sub.2 O.sub.3, Sb.sub.2 S.sub.3, Sb.sub.2 Se.sub.3, As.sub.2 S.sub.3, As.sub.2 Se.sub.3 and polyvinyl carbazole. ### Claim 13 (depends on 11) An electrophotographic member according to claim 11, further including a blocking layer at the surface side of said photoconductive layer for suppressing the injection of charges from the surface side of the photoconductive layer. ### Claim 14 (depends on 13) An electrophotographic member according to claim 13, wherein each of the two blocking layers is made of a material selected from the group consisting of SiO, SiO.sub.2, CeO.sub.2, TaO.sub.2, Al.sub.2 O.sub.3, V.sub.2 O.sub.3, Sb.sub.2 S.sub.3, Sb.sub.2 Se.sub.3, As.sub.2 S.sub.3, As.sub.2 Se.sub.2 and polyvinyl carbazole. ### Claim 15 (depends on 1, 2, 3, 4) An electrophotographic member according to any one of claims 1 to 4, further including a blocking layer at the surface side of said photoconductive layer for suppressing the injection of charges from the surface side of the photoconductive layer. ### Claim 16 (depends on 15) An electrophotographic member according to claim 15, wherein said blocking layer at the surface side of said photoconductive layer is made of a material selected from the group consisting of SiO, SiO.sub.2, CeO.sub.2, TaO.sub.2, Al.sub.2 O.sub.3, V.sub.2 O.sub.3, Sb.sub.2 S.sub.3, Sb.sub.2 Se.sub.3, As.sub.2 S.sub.3, As.sub.2 Se.sub.3, and polyvinyl carbazole. ### Claim 17 (depends on 1, 2, 3, 4) An electrophotographic member according to any one of claims 1 to 4, wherein said distance is at most 2 .mu.m. ### Claim 18 (depends on 8, 9) An electrophotographic system according to any one of claims 8 and 9, wherein said distance is at most 2 .mu.m. ### Claim 19 (depends on 1, 2, 3, 4) An electrophotographic member according to any one of claims 1 to 4, wherein the thickness of said photoconductive layer of an amorphous silicon containing hydrogen is at most 100 .mu.m. ### Claim 20 (depends on 1, 2, 3, 4) An electrophotographic member according to any one of claims 1 to 4, wherein said photoconductive layer of amorphous silicon containing hydrogen is doped with a material selected from the group consisting of carbon, boron and germanium. ### Claim 21 (depends on 1) An electrophotographic member according to claim 1, wherein said hydrogen amounts to at most 40 atomic %. ### Claim 22 (depends on 1) An electrophotographic member according to claim 1, wherein said hydrogen amounts to at most 30 atomic %. ### Claim 23 (depends on 1) An electrophotographic member according to claim 1, wherein said support is made of metal. ### Claim 24 (depends on 1) An electrophotographic member according to claim 1, wherein said support is made of an electrically insulating material with an electrode thereon.