# US 10,121,932 B1 · Tunable graphene light-emitting device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,121,932 B1 - Document ID: US10121932B1 - Status: Granted - Kind: B1 - Application number: 15/827,556 - Filed: 2017-11-30 - Granted: 2018-11-06 - Earliest claimed: 2016-11-30 - Assignees: The United States of America as represented by the Secretary of the Navy - Applicants: The United States of America AS Represented By the Secretary of the Navy - Inventors: Carlos M. Torres, Jr.; James R. Adleman; Ryan P. Lu; Kang L. Wang - Web page: https://patentgrep.com/patent/US10121932B1 ## CPC - C09K 11/65: containing carbon (in organic compounds C09K11/06) - H05B 33/02: Details - H05B 33/14: characterised by the chemical or physical composition or the arrangement of the electroluminescent material {, or by the simultaneous addition of the electroluminescent material in or onto the light source} - H10H 20/062: {Light-emitting semiconductor devices having field effect type light-emitting regions, e.g. light-emitting High-Electron Mobility Transistors} - H10H 20/826: comprising only Group IV materials - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL - H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS ## Abstract A device includes a substrate with a tunnel barrier disposed on active region defined on the substrate, a monolayer of graphene disposed on the tunnel barrier, a dielectric material disposed on the graphene, and an electrode disposed over a region of the dielectric material. A first voltage is applied across the electrode and the graphene to adjust a Fermi level within the graphene to a Fermi level position within the valence band of the graphene based upon a predetermined emission wavelength. A current is injected into the graphene's conduction band to cause the graphene to emit a broadband hot electron luminescence (HEL) spectrum of photons peaked at the predetermined emission wavelength. The device may be configured as a vertical-tunneling light-emitting hot-electron transistor. The broadband HEL photon emission spectrum emanating from the graphene may be voltage-tunable within the electromagnetic spectrum from UV to THz. ## Claims ### Claim 1 A method comprising the steps of: providing a device comprising a substrate having a tunnel barrier disposed on an active region defined on the substrate, a monolayer of graphene disposed on the tunnel barrier, a dielectric material disposed on the monolayer of graphene, and an electrode disposed on the dielectric material; applying a first voltage across the electrode and the monolayer of graphene to adjust a Fermi level within the monolayer of graphene to a Fermi level position within a valence band of the monolayer of graphene based upon a predetermined photonic emission wavelength; and applying a second voltage across the substrate and the monolayer of graphene to inject a current into a conduction band of the monolayer of graphene to cause the monolayer of graphene to emit photons at the predetermined emission wavelength. ### Claim 2 (depends on 1) The method of claim 1, wherein the predetermined emission wavelength is between about 700 nm and about 1 mm. ### Claim 3 (depends on 1) The method of claim 1, wherein the predetermined emission wavelength is between about 390 nm and about 700 nm. ### Claim 4 (depends on 1) The method of claim 1, wherein the predetermined emission wavelength is between about 270 nm and about 390 nm. ### Claim 5 (depends on 1) The method of claim 1, wherein the substrate comprises one of a metal, a semi-metal, and a semiconductor. ### Claim 6 (depends on 1) The method of claim 1, wherein the substrate comprises a compound semiconductor selected from one of elemental groups II-VI, III-V and IV. ### Claim 7 (depends on 1) The method of claim 1, wherein the substrate comprises degenerately-doped n-type silicon. ### Claim 8 (depends on 1) The method of claim 1, wherein the dielectric material comprises a dielectric having a k-value greater than about 3.8. ### Claim 9 (depends on 1) The method of claim 1, wherein the dielectric material comprises hexagonal boron nitride. ### Claim 10 (depends on 1) The method of claim 1, wherein the dielectric material comprises one of an ion-gel, an ionic liquid, and a gel polymer electrolyte. ### Claim 11 (depends on 1) The method of claim 1, wherein the tunnel barrier comprises one of MgO, SiO2, monolayer hexagonal boron nitride, multilayer hexagonal boron nitride, and Gd2O3. ### Claim 12 (depends on 1) The method of claim 1, wherein the current is electrically-induced. ### Claim 13 (depends on 1) The method of claim 1, wherein the current is photo-induced. ### Claim 14 A device comprising: a substrate; a tunnel barrier disposed on an active region defined on the substrate; at least one monolayer of graphene disposed on the tunnel barrier; a dielectric material disposed on the monolayer of graphene, an electrode disposed over a portion of the dielectric material; a first electrical contact disposed over a portion of the monolayer of graphene; a second electrical contact disposed over a portion of the dielectric material; a third electrical contact disposed over a portion of the substrate; a first voltage source connected between the first electrical contact and the second electrical contact, the first voltage source configured to apply a first voltage to adjust a Fermi level within the monolayer of graphene to a Fermi level position within a valence band of the monolayer of graphene based upon a predetermined emission wavelength; and a second voltage source connected between the first electrical contact and the third electrical contact, the second voltage source configured to apply a second voltage to inject a current into a conduction band of the monolayer of graphene to cause the monolayer of graphene to emit photons at the predetermined emission wavelength. ### Claim 15 (depends on 14) The device of claim 14, wherein the substrate comprises degenerately-doped n-type silicon and the at least one monolayer of graphene is p-doped. ### Claim 16 (depends on 14) The device of claim 14, wherein the at least one monolayer of graphene comprises more than two separate monolayers of graphene each featuring a band structure with linear energy dispersion relation near the Dirac (K/K′) point. ### Claim 17 (depends on 16) The device of claim 16, wherein the two separate monolayers of graphene are separated by atomically-thin layered materials. ### Claim 18 (depends on 17) The device of claim 17, wherein the atomically-thin layered materials comprise one of hexagonal boron nitride and transition metal dichalcogenides. ### Claim 19 (depends on 14) The device of claim 14, wherein the dielectric material comprises one of HfO2, Al2O3, TiO2, monolayer hexagonal boron nitride, and multilayer hexagonal boron nitride. ### Claim 20 (depends on 14) The device of claim 14, wherein the dielectric material comprises one of an ion-gel, an ionic liquid, and a gel polymer electrolyte. ### Claim 21 (depends on 14) The device of claim 14, wherein the tunnel barrier comprises one of MgO, SiO2, monolayer hexagonal boron nitride, multilayer hexagonal boron nitride, and Gd2O3. ### Claim 22 (depends on 14) The device of claim 14, wherein the photons are emitted with a broadband hot electron luminescence spectrum peaked at the predetermined photon emission wavelength. ### Claim 23 (depends on 14) The device of claim 14, wherein the current injected into the conduction band of the monolayer of graphene is modulated at frequencies of up to about 10 THz. ### Claim 24 A device comprising: a substrate; a tunnel barrier disposed on an active region defined on the substrate; at least one monolayer of graphene disposed on the tunnel barrier; a dielectric material disposed on the monolayer of graphene, an optically-transparent electrode disposed over a portion of the dielectric material; a first electrical contact disposed over a portion of the monolayer of graphene lying outside of the active region defined on the substrate; a second electrical contact disposed over a portion of the dielectric material and electrically connected to the optically-transparent electrode in the active region defined on the substrate; a third electrical contact disposed over a portion of the substrate; a first voltage source connected between the first electrical contact and the second electrical contact, the first voltage source configured to apply a first voltage to adjust a Fermi level within the monolayer of graphene to a Fermi level position within a valence band of the monolayer of graphene based upon a predetermined emission wavelength; and a second voltage source connected between the first electrical contact and the third electrical contact, the second voltage source configured to apply a second voltage to inject a current into a conduction band of the monolayer of graphene to cause the monolayer of graphene to emit photons at the predetermined emission wavelength.