  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 $10^5$ cm$^2$/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 ${\mu}$eV. Our results demonstrate the
viability of this platform for hybrid topological superconductor devices.
