Niobium-germanium superconducting photon detector

Patent metadata

Field	Value
Publication number	US-10197440-B2
Application number	US-201816012520-A
Country	US
Kind code	B2
Filing date	Jun 19, 2018
Priority date	Jun 15, 2017
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

The various embodiments described herein include methods, devices, and systems for fabricating and operating niobium-germanium-based superconducting devices. In one aspect, a device includes a superconducting nanowire composed of niobium-germanium, a protective layer configured to inhibit oxidation of the superconducting nanowire, and a current source configured to supply a current to the superconducting nanowire. In another aspect, a method of fabrication includes: (1) depositing a layer of niobium-germanium on a substrate; (2) removing one or more portions of the layer of niobium-germanium to define one or more nanowires; and (3) depositing a protective layer over the one or more nanowires, the protective layer adapted to inhibit oxidation of niobium-germanium in the one or more nanowires.

First claim

What is claimed is:

1. A photodetector device, comprising:
a superconducting nanowire composed of niobium-germanium;
a protective layer configured to inhibit oxidation of the superconducting nanowire; and
a current source configured to supply a current to the superconducting nanowire.

2. The device of claim 1 , wherein the superconducting nanowire is adapted to operate in a superconducting state at temperatures between 3 Kelvin and 20 Kelvin.

3. The device of claim 1 , wherein at least a portion of the superconducting nanowire consists essentially of the niobium-germanium.

4. The device of claim 1 , wherein the niobium-germanium includes niobium and germanium in a ratio between 3:1 and 3.5:1.

5. The device of claim 1 , further comprising a layer of aluminum nitride located over the superconducting nanowire.

6. The device of claim 1 , wherein the protective layer encapsulates at least a portion of the niobium-germanium in the superconducting nanowire.

7. The device of claim 6 , further comprising a layer of aluminum nitride located over the superconducting nanowire, wherein the protective layer encapsulates at least a portion of the layer of aluminum nitride and at least the portion of the niobium-germanium in the superconducting nanowire.

8. The device of claim 1 , wherein the superconducting nanowire has a width between 10 nm and 50 nm.

9. The device of claim 1 , wherein the superconducting nanowire has a thickness between 2 nm and 10 nm.

10. The device of claim 1 , wherein the current is adapted to be less than a threshold superconducting current of the superconducting nanowire.

11. The device of claim 10 , further comprising a second circuit coupled to the superconducting nanowire; and
wherein the photodetector device is configured to, in response to receiving light of first intensity at the superconducting nanowire, transition the superconducting nanowire from a superconducting state to a non-superconducting state, thereby redirecting at least a portion of the current toward the second circuit.

12. The device of claim 11 , wherein the superconducting nanowire is configured to operate in the superconducting state prior to receiving the light of first intensity.

13. A method, comprising:
depositing a layer of niobium-germanium on a substrate;
removing one or more portions of the layer of niobium-germanium to define one or more nanowires; and
depositing a protective layer over the one or more nanowires, the protective layer adapted to inhibit oxidation of niobium-germanium in the one or more nanowires.

14. The method of claim 13 , wherein the layer of niobium-germanium is deposited via physical vapor deposition.

15. The method of claim 13 , wherein the layer of niobium-germanium is deposited via sputtering.

16. The method of claim 13 , further comprising depositing a layer of aluminum nitride over the layer of niobium-germanium prior to depositing the protective layer.

17. The method of claim 16 , wherein:
the layer of aluminum nitride is deposited over the layer of niobium-germanium prior to removing the one or more portions of the layer of niobium-germanium; and
removing the one or more portions of the layer of niobium-germanium includes removing corresponding one or more portions of the layer of aluminum nitride.

18. The method of claim 16 , further comprising annealing the layer of niobium-germanium and the layer of aluminum nitride.

19. The method of claim 13 , wherein the depositing the layer of niobium-germanium, the removing of the one or more portions, and the depositing of the protective layer are performed within a same vacuum state.

20. The method of claim 13 , further comprising:
forming a first circuit connected to a first end of a respective nanowire of the one or more nanowires and configured to supply a first current to the respective nanowire, wherein the first current is less than a first maximum superconducting current of the respective nanowire; and
forming a second circuit connected to the first end of the respective nanowire, the second circuit configured to detect a current flowing through the second circuit.

21. The method of claim 13 , wherein the wherein the layer of niobium-germanium is deposited at a temperature of less than 400 degrees Celsius.

Assignees

• Psiquantum Corp
• Psiquantum Corp

Inventors

• Najafi Faraz

Classifications

• G01J1/42 Primary

  using electric radiation detectors (optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10) · CPC title

• G01J2005/208

  superconductive · CPC title

• G01J2001/442

  Single-photon detection or photon counting · CPC title

• G01J5/20

  using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices · CPC title

• G01J5/046

  Materials; Selection of thermal materials · CPC title