Method for tuning work function using surface photo voltage and producing ultra-low-work-function surfaces, and devices operational therewith

Patent metadata

Field	Value
Publication number	US-12046439-B2
Application number	US-202117538280-A
Country	US
Kind code	B2
Filing date	Nov 30, 2021
Priority date	Jul 16, 2013
Publication date	Jul 23, 2024
Grant date	Jul 23, 2024

Abstract

The embodiments provide a thermionic emission device and a method for tuning a work function in a thermionic emission device is provided. The method includes illuminating an N type semiconductor material of a first member of a thermionic emission device, wherein a work function of the N type semiconductor material is lowered by the illuminating. The method includes collecting, on one of the first member or a second member of the thermionic emission device, electrons emitted from one of the first member or the second member.

First claim

What is claimed is:

1. A method for tuning a work function in a thermionic emission device, comprising:
illuminating an N type semiconductor material of a first member of a thermionic emission device, wherein a work function of the N type semiconductor material is lowered by the illuminating; and
collecting, on one of the first member or a second member of the thermionic emission device, electrons emitted from one of the first member or the second member;
heating the second member, wherein the second member acts as an emitter of electrons, wherein the first member of the thermionic emission device acts as a collector of the electrons, and wherein the thermionic emission device acts as a thermionic energy converter; and
wherein illuminating the N type semiconductor material comprises illuminating the N type semiconductor material with light that has energy greater than the bandgap of the N type semiconductor material.

2. The method of claim 1 , wherein the first member further comprises a work function lowering coating.

3. The method of claim 2 , wherein the work function lowering coating comprises at least one element selected from the group consisting of: cesium, barium, strontium, and calcium.

4. The method of claim 3 , wherein the work function lowering coating comprises cesium oxide.

5. The method of claim 2 , wherein the work function lowering coating comprises cesium.

6. The method of claim 2 , wherein the N type semiconductor material comprises a material selected from the group consisting of: gallium arsenide, silicon, gallium nitride, silicon carbide, and zinc oxide.

7. The method of claim 2 , wherein the N type semiconductor material comprises at least one of gallium arsenide or silicon.

8. The method of claim 2 , wherein the N type semiconductor material comprises N type gallium arsenide.

9. The method of claim 2 , wherein the N type semiconductor material comprises N type silicon.

10. The method of claim 1 , wherein illuminating the N type semiconductor material comprises receiving light from a source external to the second member, wherein the N type semiconductor material is illuminated by the light.

11. The method of claim 1 , wherein the N type semiconductor material comprises a material selected from the group consisting of: gallium arsenide, silicon, gallium nitride, silicon carbide, and zinc oxide.

12. The method of claim 1 , wherein the N type semiconductor material comprises at least one of gallium arsenide or silicon.

13. The method of claim 1 , wherein the N type semiconductor material comprises N type gallium arsenide.

14. The method of claim 1 , wherein the N type semiconductor material comprises N type silicon.

15. A method for tuning a work function in a thermionic emission device, comprising:
illuminating an N type semiconductor material of a first member of a thermionic emission device, wherein a work function of the N type semiconductor material is lowered by the illuminating;
collecting, on one of the first member or a second member of the thermionic emission device, electrons emitted from one of the first member or the second member; and
applying a bias voltage between the first member and the second member, wherein the second member is biased to a positive voltage with respect to the first member, wherein the first member acts as an emitter of electrons, wherein the second member acts as a collector of the electrons, and wherein the thermionic emission device acts as a refrigeration mode device with the first member reducing a temperature as a result of the illuminating and the applying the bias voltage.

16. A method for tuning a work function in a thermionic emission device, comprising:
illuminating an N type semiconductor material of a first member of a thermionic emission device, wherein a work function of the N type semiconductor material is lowered by the illuminating;
collecting, on one of the first member or a second member of the thermionic emission device, electrons emitted from one of the first member or the second member; and
illuminating a P type semiconductor material of the second member, wherein the second member acts as a cathode, wherein the first member acts as an anode, and wherein the thermionic emission device acts as a photon enhanced thermionic emission (PETE) energy converter.

Assignees

• Univ Leland Stanford Junior

Inventors

• Riley Daniel
• Sahasrabuddhe Kunal
• Bargatin Igor
• Schwede Jared
• Shen Zhixun
• Melosh Nicholas A

Classifications

• H01J1/20

  Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment · CPC title

• H01J1/135 Primary

  Circuit arrangements therefor, e.g. for temperature control · CPC title

• H01J1/15 Primary

  Cathodes heated directly by an electric current · CPC title

• H01J45/00

  Discharge tubes functioning as thermionic generators {(structural combination of fuel element with thermoelectric element G21C3/40; nuclear power plants using thermionic converters G21D7/04; structural combination of a radioactive source with a thermionic converter, e.g. radioisotope batteries G21H1/10; generators in which thermal or kinetic energy is converted into electrical energy by ionisation of a fluid and removal of the charge therefrom H02N3/00)} · CPC title