  High mobility, strong spin-orbit coupling, and large Land\'e g-factor make
the two-dimensional electron gas (2DEG) in InAs quantum wells grown on
nearly-lattice-matched GaSb substrates an attractive platform for mesoscopic
quantum transport experiments. Successful operation of mesoscopic devices
relies on three key properties: electrical isolation from the substrate;
ability to fully deplete the 2DEG and control residual sidewall conduction with
lithographic gates; and high mobility to ensure ballistic transport over
mesoscopic length scales. Simultaneous demonstration of these properties has
remained elusive for InAs 2DEGs on GaSb substrates. Here we report on
heterostructure design, molecular beam epitaxy growth, and device fabrication
that result in high carrier mobility and full 2DEG depletion with minimal
residual edge conduction. Our results provide a pathway to fully-controlled
2DEG-based InAs mesoscopic devices.
