The origin of gate hysteresis in p-type Si-doped AlGaAs/GaAs heterostructures

Gate instability and hysteresis in Si-doped p-type AlGaAs/GaAs heterostructures impedes the development of nanoscale hole devices, which are of interest for topics from quantum computing to novel spin physics. We report an extended study conducted using matched n-type and p-type heterostructures, with and without insulated gates, aimed at understanding the origin of the hysteresis. We show the hysteresis is not due to the inherent ‘leakiness’ of gates on p-type heterostructures, as commonly believed. Instead, hysteresis arises from a combination of GaAs surface-state trapping and charge migration in the doping layer.