# US 8,785,908 B2 · Materials, fabrication equipment, and methods for stable, sensitive photodetectors and image sensors made therefrom > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,785,908 B2 - Document ID: US8785908B2 - Status: Granted - Kind: B2 - Application number: 13/473,020 - Filed: 2012-05-16 - Published: 2012-11-08 - Granted: 2014-07-22 - Earliest claimed: 2008-04-18 - Assignees: InVisage Technologies, Inc. - Applicants: Igor Constantin Ivanov; Edward Hartley Sargent; Hui Tian - Inventors: Igor Constantin Ivanov; Edward Hartley Sargent; Hui Tian - Web page: https://patentgrep.com/patent/US8785908B2 ## CPC - H10F 30/21: the devices being sensitive to infrared, visible or ultraviolet radiation - H10F 10/16: Photovoltaic cells having only PN heterojunction potential barriers - H10F 30/10: the devices being sensitive to infrared radiation, visible or ultraviolet radiation, and having no potential barriers, e.g. photoresistors - H10F 30/222: the potential barrier being a PN heterojunction - H10F 39/802: {Geometry or disposition of elements in pixels, e.g. address-lines or gate electrodes} - H10F 77/12: Active materials - H10F 77/127: {comprising only Group IV-VI or only Group II-IV-VI chalcogenide materials, e.g. PbSnTe} - H10F 77/1433: {Quantum dots} - H10F 77/1625: {Semiconductor nanoparticles embedded in semiconductor matrix} - H10F 77/20: Electrodes - Y02E 10/50: Photovoltaic [PV] energy - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract Optically sensitive devices include a device comprising a first contact and a second contact, each having a work function, and an optically sensitive material between the first contact and the second contact. The optically sensitive material comprises a p-type semiconductor, and the optically sensitive material has a work function. Circuitry applies a bias voltage between the first contact and the second contact. The optically sensitive material has an electron lifetime that is greater than the electron transit time from the first contact to the second contact when the bias is applied between the first contact and the second contact. The first contact provides injection of electrons and blocking the extraction of holes. The interface between the first contact and the optically sensitive material provides a surface recombination velocity less than 1 cm/s. ## Claims ### Claim 1 An optically sensitive device comprising: a first contact; a second contact; and an optically sensitive material comprising a cross-linking agent, at least one functional group of the cross-linking agent binding the first contact, the combination of the first contact, the cross-linking agent binding the first contact, and the optically sensitive layer comprise a Schottky contact, wherein electrons are withdrawn with high efficiency, and holes are injected with low efficiency. ### Claim 2 (depends on 1) The device of claim 1, wherein the cross-linking agent comprises at least one thiol-terminated ligand from a group comprising benzenedithiol, ethanedithiol, and butanedithiol, or a multidentate molecule that includes a backbone, sidegroups or endgroups including thiols, amines, or carboxylates, and functional groups to confer solubility in polar, nonpolar, and partially polar solvents. ### Claim 3 (depends on 1) The device of claim 1, wherein the optically sensitive material comprises a plurality of nanoparticles. ### Claim 4 (depends on 1) The device of claim 1, wherein the optically sensitive material comprises nanoparticles selected from the group consisting of PbS, PbSe, PbTe, CdS, CdSe, CdTe, Si, Ge, and C. ### Claim 5 (depends on 1) The device of claim 1, wherein the optically sensitive material comprises a plurality of interconnected nanoparticles. ### Claim 6 (depends on 1) The device of claim 1, wherein the first contact and the second contact are separated by a distance in the range of about 200 nm to about 2 μm. ### Claim 7 (depends on 1) The device of claim 1, wherein the first contact comprises a material selected from the group consisting of Al, Ag, In, Mg, Ca, Li, Cu, Ni, NiS, TiN, TaN, TiO2, TixNy, ITO, Ru, TiSi, WSi2, TiOx doped with B, TiOx doped with C, TiOx doped with Co, TiOx doped with Fe, TiOx doped with Nd, and TiOx doped with N. ### Claim 8 An optically sensitive device, comprising: a first contact; a second contact; an interface layer; and an optically sensitive material comprising a cross-linking agent, at least one functional group of the cross-linking agent binding the interface layer, the combination of the first contact, the cross-linking agent binding the interface layer, and the optically sensitive layer comprise a junction wherein electrons are withdrawn with high efficiency, and holes are injected with low efficiency. ### Claim 9 (depends on 8) The optically sensitive device of claim 8, where the cross-linking agent comprises at least one thiol-terminated ligand from a group comprising benzenedithiol, ethanedithiol, and butanedithiol, or a multidentate molecule that includes a backbone, sidegroups or endgroups including thiols, amines, or carboxylates, and functional groups to confer solubility in polar, nonpolar, and partially polar solvents. ### Claim 10 (depends on 8) The optically sensitive device of claim 8, wherein the first contact comprises a material selected from the group consisting of Al, Ag, In, Mg, Ca, Li, Cu, Ni, NiS, TiN, TaN, TiO2, TixNy, ITO, Ru, TiSi, WSi2, TiOx doped with B, TiOx doped with C, TiOx doped with Co, TiOx doped with Fe, TiOx doped with Nd, and TiOx doped with N. ### Claim 11 (depends on 8) The optically sensitive device of claim 8, where the interface layer comprises a pure, clean surface of the metal of the first contact. ### Claim 12 (depends on 8) The optically sensitive device of claim 8, where the interface layer includes an oxide. ### Claim 13 (depends on 12) The optically sensitive device of claim 12, where the oxide is formed through exposure of the metal of the first contact to water, oxygen, or an oxidizing species. ### Claim 14 (depends on 8) The optically sensitive device of claim 8, where the interface layer comprises TiO2, TiOxNy, Al2O3, Au2O3, PtO, PtO2, Ni2O3, WO3, PdO, ITO, or oxygen-rich ITO. ### Claim 15 (depends on 8) The optically sensitive device of claim 8, where the thickness of the interface layer is in the range of about 2 nm to about 20 nm. ### Claim 16 (depends on 8) The optically sensitive device of claim 8, where a portion of the interface layer has a bandgap that is larger than about 2 eV.