Near-surface InAs two-dimensional electron gas on a GaAs substrate: Characterization and superconducting proximity effect
Máté Sütő, Tamás Prok, Péter Makk, Magdhi Kirti, G. Biasiol, Szabolcs Csonka, Endre Tóvári
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 ${10}^{5}\phantom{\rule{0.28em}{0ex}}{\mathrm{cm}}^{2}/\mathrm{Vs}$. 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 $125\phantom{\rule{0.28em}{0ex}}\mathrm{\ensuremath{\mu}}\mathrm{eV}$. Our results suggest that this InAs system is a viable platform for use in hybrid topological superconductor devices.