Repairing the surface of InAs-based topological heterostructures
Sebastian Pauka, J. D. S. Witt, Claudine Nì. Allen, B. Harlech-Jones, A. Jouan, Geoffrey C. Gardner, Sergei Gronin, Tong Wang, Candice Thomas, Michael J. Manfra, Jan Gukelberger, John King Gamble, D. J. Reilly, Maja C. Cassidy
Abstract
Candidate systems for topologically-protected qubits include two-dimensional electron gases (2DEGs) based on heterostructures exhibiting a strong spin–orbit interaction and superconductivity via the proximity effect. For InAs- or InSb-based materials, the need to form shallow quantum wells to create a hard-gapped p-wave superconducting state often subjects them to fabrication-induced damage, limiting their mobility. Here, we examine scattering mechanisms in processed InAs 2DEG quantum wells and demonstrate a means of increasing their mobility via repairing the semiconductor–dielectric interface. Passivation of charged impurity states with an argon–hydrogen plasma results in a significant increase in the measured mobility and reduction in its variance relative to untreated samples, up to 45 300 cm2/(V s) in a 10 nm deep quantum well.