Systems, devices, and methods for resistance metrology using graphene with superconducting components
A quantum Hall resistance apparatus is to improve resistance standards and includes a substrate, a graphene epitaxially grown on the substrate and having a plurality of first contact patterns at edges of the graphene, a plurality of contacts, each including a second contact pattern and configured to connect to a corresponding first contact pattern, and a protective layer configured to protect the graphene and to increase adherence between the first contact patterns and the second contact patterns. The contacts become a superconductor at a temperature lower than or equal to a predetermined temperature and under up to a predetermined magnetic flux density.
1. A quantum Hall resistance apparatus to improve resistance standards, the quantum Hall resistance apparatus comprising:
a substrate;
a plurality of Hall bars made of graphene electrical conduction layer, which is epitaxially grown on the substrate, each Hall bar having a plurality of first contact patterns at edges thereof;
a plurality of contacts, each including a second contact pattern and configured to connect to a corresponding first contact pattern; and
a protective layer configured to protect first contact patterns and to increase adherence between the first contact patterns and the second contact patterns,
wherein the plurality of contacts become a superconductor at a temperature lower than or equal to a predetermined temperature and under up to a predetermined magnetic flux density.
2. The quantum Hall resistance apparatus according to claim 1 , wherein each first contact pattern includes at least two extensions therefrom.
3. The quantum Hall resistance apparatus according to claim 2 , wherein each second contact pattern fits to a corresponding first contact pattern.
4. The quantum Hall resistance apparatus according to claim 1 , wherein the predetermined temperature is 12.5 Kelvin.
5. The quantum Hall resistance apparatus according to claim 1 , wherein the predetermined magnetic flux density is 9 Tesla.
6. The quantum Hall resistance apparatus according to claim 1 , wherein the protective layer is formed of palladium and gold.
7. The quantum Hall resistance apparatus according to claim 1 , wherein the plurality of contacts are made of niobium, titanium, nitrogen, or any combination thereof.
8. The quantum Hall resistance apparatus according to claim 1 , wherein the graphene is a mono-layer.
9. The quantum Hall resistance apparatus according to claim 1 , wherein the quantum Hall resistance apparatus is functionalized with chromium tricarbonyl (Cr(CO) 3 ).
10. The quantum Hall resistance apparatus according to claim 1 , wherein the substrate is a 4H—SiC(0001) semi-insulating substrate with a miscut, relative to the (0001) atomic plane of the 4H—SiC(0001), which is less than or equal to 0.10°.
11. The quantum Hall resistance apparatus according to claim 1 , wherein the plurality of contacts with respect to the plurality of Hall bars are connected in series, parallel, or combination thereof to make a resistance standard.
12. A method for making a quantum Hall bar resistance apparatus to improve resistance standards, the method comprising:
providing a substrate;
epitaxially growing a graphene to form an electrical conduction layer on the substrate;
etching the graphene to make a plurality of Hall bars, each including a plurality of first contact patterns at edges thereof;
performing lithographic processes to lay a protective layer configured to protect the plurality of first contact patterns; and
adding a plurality of contacts over the protective layer, each contact having a second contact pattern to connect to a corresponding first contact pattern,
wherein the plurality of contacts become a superconductor at a temperature lower than or equal to a predetermined temperature and under up to a predetermined magnetic flux density.
13. The method according to claim 12 , wherein epitaxially growing the graphene includes:
placing the substrate into a furnace;
purging the substrate with argon; and
step-wisely increasing a temperature in the furnace to 1875° C. at a same rate in environment including argon and hydrogen.
14. The method according to claim 13 , wherein the hydrogen is removed from the furnace at 1050° C.
15. The method according to claim 13 , wherein a silicon face of the substrate is in contact with a polished graphite slab in the furnace.
16. The method according to claim 12 , wherein the predetermined temperature is 12.5 Kelvin.
17. The method according to claim 12 , wherein the predetermined magnetic flux density is 9 Tesla.
18. The method according to claim 12 , wherein the protective layer is formed of palladium and gold.
19. The method according to claim 12 , further comprising:
functionalizing the quantum Hall bar resistance apparatus with chromium tricarbonyl (Cr(CO) 3 ).
20. The method according to claim 12 , wherein the contacts are made of niobium, titanium, nitrogen, and any combination thereof.
21. The method according to claim 12 , further comprising:
mounting the quantum Hall bar resistance apparatus over a leadless chip carrier; and
bonding wires between the quantum Hall bar resistance apparatus and the leadless chip carrier.
22. A quantum Hall resistance apparatus to improve resistance standards, the quantum Hall resistance apparatus comprising:
a substrate;
one or more Hall bars epitaxially grown on the substrate, each Hall bar having a plurality of first contact patterns at edges thereof;
one or more contacts, each including a second contact pattern connected to a corresponding first contact pattern; and
a protective layer between the first contact patterns and the second contact patterns,
wherein the one or more contacts become a superconductor under one or more of the following conditions: (i) at a temperature of 12.5 Kelvin or less; or (ii) at a magnetic flux density of 9 Tesla or lower.