	US 11,810,968 B1
	Method for induced quantum dots for material characterization, qubits, and quantum computers
Charles George Tahan, Kensington, MD (US); Rousko Todorov Hristov, College Park, MD (US); Yun-Pil Shim, Marriotsville, MD (US); and Hilary Hurst, Washington, DC (US)
Assigned to Government of the United States, as represented by the Director, National Security Agency
Filed by The Government of the United States as represented by the Director, National Security Agency, Ft. George G. Meade, MD (US)
Filed on Jul. 14, 2022, as Appl. No. 17/864,617.
Application 17/864,617 is a division of application No. 16/552,764, filed on Aug. 27, 2019, granted, now 11,444,184.
Claims priority of provisional application 62/723,315, filed on Aug. 27, 2018.
Int. Cl. H01L 29/66 (2006.01); H01L 29/165 (2006.01); G06N 10/00 (2022.01); H01L 21/265 (2006.01); H01L 29/06 (2006.01); H01L 29/423 (2006.01)

CPC H01L 29/66977 (2013.01) [G06N 10/00 (2019.01); H01L 21/26513 (2013.01); H01L 29/0665 (2013.01); H01L 29/165 (2013.01); H01L 29/42312 (2013.01)]

4 Claims

1. A method, comprising:

positioning at least one lead wire of a gate chip at a distance of less than 10 nm from a semiconductor heterostructure, the lead wire having a cross sectional width between 5 nm and 30 nm, the semiconductor heterostructure comprising a surface layer and at least one subsurface layer;

inducing a quantum dot in the semiconductor heterostructure, wherein an electrostatic potential is induced in the subsurface layer by applying a voltage between 0.01 V and 0.2 V to the lead wire such than an orbital energy for a given charge carrier of the induced quantum dot is larger than an energy level of an effective temperature bath;

loading a charge carrier into the subsurface layer;

detecting the charge carrier in the subsurface layer of the semiconductor heterostructure by:

emitting a radio-frequency pulse using a resonator having a Q factor of at least 10³coupled to the at least one lead wire of the gate chip;

detecting a reflected pulse of the emitted radio-frequency pulse; and

determining a phase shift of the reflected pulse relative to the emitted radio-frequency pulse; and

characterizing the quantum dot by measuring a valley splitting of the quantum dot.