  GaAs was central to the development of quantum devices but is rarely used for
nanowire-based quantum devices with InAs, InSb and SiGe instead taking the
leading role. p-type GaAs nanowires offer a path to studying strongly-confined
0D and 1D hole systems with strong spin-orbit effects, motivating our
development of nanowire transistors featuring Be-doped p-type GaAs nanowires,
AuBe alloy contacts and patterned local gate electrodes towards making
nanowire-based quantum hole devices. We report on nanowire transistors with
traditional substrate back-gates and EBL-defined metal/oxide top-gates produced
using GaAs nanowires with three different Be-doping densities and various AuBe
contact processing recipes. We show that contact annealing only brings small
improvements for the moderately-doped devices under conditions of lower anneal
temperature and short anneal time. We only obtain good transistor performance
for moderate doping, with conduction freezing out at low temperature for
lowly-doped nanowires and inability to reach a clear off-state under gating for
the highly-doped nanowires. Our best devices give on-state conductivity 95 nS,
off-state conductivity 2 pS, on-off ratio ~$10^{4}$, and sub-threshold slope 50
mV/dec at T = 4 K. Lastly, we made a device featuring a moderately-doped
nanowire with annealed contacts and multiple top-gates. Top-gate sweeps show a
plateau in the sub-threshold region that is reproducible in separate cool-downs
and indicative of possible conductance quantization highlighting the potential
for future quantum device studies in this material system.
