Tahan Research

Yun-Pil Shim, Rusko Ruskov, Hilary M. Hurst, and Charles Tahan

Appl. Phys. Lett. 114, 152105 (2019); https://doi.org/10.1063/1.5053756

ABSTRACT
We propose a non-destructive means of characterizing a semiconductor wafer via measuring the parameters of an induced quantum dot on the material system of interest with a separate probe chip that can also house the measurement circuitry. We show that a single wire can create the dot, determine if an electron is present, and be used to measure critical device parameters. Adding more wires enables more complicated (potentially multi-dot) systems and measurements. As one application for this concept, we consider a silicon metal-oxide-semiconductor and silicon/silicon-germanium quantum dot qubits relevant to quantum computing and show how to measure low-lying excited states (so-called “valley” states). This approach provides an alternative method for the characterization of parameters that are critical for various semiconductor-based quantum dot devices without fabricating such devices.

Proposed probe chip a potential shortcut for quantum device manufacturing cycle 

Alternative method of characterizing semiconductor material properties with a separate probe chip that induces quantum dots could speed optimization of quantum dot spin qubits.

Shim et al. propose a new method to make the characterization process of these devices easier — by incorporating separate probe chips that would allow quick measurements of the semiconductors hosting these qubit devices.
The proposed separate probe chip possesses circuitry capable of both inducing quantum dots on the target semiconductor and measuring properties of the semiconductor. Inducing quantum dots instead of fabricating them would allow nondestructive characterization of the qubit, making the characterization process easier.

https://doi.org/10.1063/1.5100278