Anisotropic conducting films for electromagnetic radiation applications

• US 9,059,335 B2
• Filed: 02/27/2013
• Issued: 06/16/2015
• Est. Priority Date: 02/27/2013
• Status: Active Grant

• Current Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Original Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Inventors: Cavallo, Francesca, Lagally, Max G., Rojas-Delgado, Richard
• Primary Examiner(s): Berman, Jack
• Assistant Examiner(s): CHUNG, KEVIN T
• Application Number:
  US13/778,770
• Publication Number:
  US 20140239201A1
• Time in Patent Office: 839 Days
• Field of Search: 250/493.1, 438/977
• US Class Current: 1/1
• CPC Class Codes: H01L 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 29/1606 Graphene
• CPC Class Codes: H01L 31/00 Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof H10K30/00 takes precedence; devices consisting of a plurality of solid state components formed in, or on, a common substrate, other than combinations of radiation-sensitive components with one or more electric light sources, H01L27/00
• CPC Class Codes: H10N 99/00 Subject matter not provided for in other groups of this subclass

Abstract

Electronic devices for the generation of electromagnetic radiation are provided. Also provided are methods for using the devices to generate electromagnetic radiation. The radiation sources include an anisotropic electrically conducting thin film that is characterized by a periodically varying charge carrier mobility in the plane of the film. The periodic variation in carrier mobility gives rise to a spatially varying electric field, which produces electromagnetic radiation as charged particles pass through the film.

Claims

1. An electromagnetic radiation source comprising:

a substrate having a surface, the surface comprising a plurality of surface segments of a first material and a plurality of surface segments of a second material, wherein the surface segments of the first and second materials are arranged in a periodic pattern;

an electrically conducting film comprising an electrically conducting material disposed over the surface of the substrate;

first and second electrical contacts in electrical communication with the electrically conducting film; and

a voltage source configured to apply a voltage across the electrically conducting film, wherein the voltage source and the first and second electrical contacts are configured to induce charge carriers to pass through the plane of the electrically conducting film parallel to the surface of the substrate;

wherein the mobility of charge carriers in regions of the electrically conducting film that are disposed on surface segments of the first material differs from the mobility of the charge carriers in regions of the electrically conducting film that are disposed on surface segments of the second material, such that the charge carriers have a periodically varying mobility within the plane of the electrically conducting film;

and further wherein the electrically conducting film is characterized in that the periodically varying mobility of the charge carriers in the electrically conducting film results in the emission of electromagnetic radiation from the electrically conducting film when the charge carriers pass through the electrically conducting film.

2. The source of claim 1, wherein the electrically conducting film is a single layer of graphene.

3. The source of claim 2, wherein at least one of the first and second materials is silicon, germanium or silicon dioxide.

4. The source of claim 1, wherein the first material is a gas-phase material and the second material is one that provides charge carriers in regions of the electrically conducting film that are disposed on surface segments of the second material with a lower mobility than in regions of the electrically conducting films that are disposed over the gas-phase material.

5. The source of claim 4, wherein the gas-phase material comprises an inert gas.

6. The source of claim 4, wherein the gas-phase material has a gas pressure less than atmospheric pressure.

7. The source of claim 1, wherein the periodic pattern comprises repeating AB units, wherein A represents the first material and B represents the second material.

8. The source of claim 1, wherein the periodicity of the periodic pattern of the surface segments is configured such that terahertz radiation is generated when the charge carriers pass through the electrically conducting film.

9. The source of claim 7, wherein the periodicity of the AB units is configured such that terahertz radiation is generated when the charge carriers pass through the electrically conducting film.

10. The source of claim 1, wherein the mobility of the charge carriers in the regions of the electrically conducting film that are disposed on surface segments of the first material is at least twice the mobility of the charge carriers in regions of the electrically conducting film that are disposed on surface segments of the second material.

12. A method of generating electromagnetic radiation using the source of claim 1, the method comprising applying a voltage across the electrically conducting film to induce a flow of charge carriers through the plane of the electrically conducting film parallel to the surface of the substrate, wherein the periodically varying mobility of the charge carriers in the electrically conducting film results in the emission of the electromagnetic radiation from the electrically conducting film.

13. The method of claim 12, wherein the electromagnetic radiation comprises terahertz radiation.

15. The source of claim 1, wherein the first material or the second material is a gas-phase material.

11. An electromagnetic radiation source comprising:

a substrate having a surface, the surface comprising a plurality of surface segments of a first material and a plurality of surface segments of a second material, wherein the surface segments of the first and second materials are arranged in a periodic striped pattern;

an electrically conducting film comprising graphene;

first and second electrical contacts in electrical communication with the grapheme; and

a voltage source configured to apply a voltage across the graphene, wherein the voltage source and the first and second electrical contacts are configured to induce electrons to pass through the plane of the graphene parallel to the surface of the substrate;

wherein the mobility of electrons in regions of the graphene that are disposed on surface segments of the first material differs from the mobility of electrons in regions of the graphene that are disposed on surface segments of the second material, such that the electrons have a periodically varying mobility within the plane of the graphene;

and further wherein the graphene is characterized in that the periodically varying mobility of the electrons in the graphene results in the emission of terahertz radiation from the graphene when the electrons pass through the graphene.

14. A method of generating terahertz radiation using the source of claim 11, the method comprising applying a voltage across the electrically conducting film to induce a flow of electrons through the graphene, wherein the periodically varying mobility of the electrons in the graphene results in the emission of the electromagnetic radiation from the graphene.

16. The source of claim 11, wherein the first material or the second material is a gas-phase material.