Near-surface InAs two-dimensional electron gas on a GaAs substrate: Characterization and superconducting proximity effect

Authors: Máté Sütő, Tamás Prok, Péter Makk, Magdhi Kirti, Giorgio Biasiol, Szabolcs Csonka, and Endre Tóvári

Phys. Rev. B 106, 235404 – Published 5 December 2022

Abstract: We have studied a near-surface two-dimensional electron gas based on an InAs quantum well on a GaAs substrate. In devices without a dielectric layer we estimated large electron mobilities on the order of 105cm2/Vs. We have observed quantized conductance in a quantum point contact, and determined the g factor. Using samples with an epitaxial Al layer, we defined multiple Josephson junctions and found the critical current to be gate tunable. Based on multiple Andreev reflections the semiconductor-superconductor interface is transparent, with an induced gap of 125μeV. Our results suggest that this InAs system is a viable platform for use in hybrid topological superconductor devices.