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 10⁵ cm²/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 μeV. Our results demonstrate the viability of this platform for hybrid topological superconductor devices.