  The transport of holes through p-doped wurtzite bulk GaN and AlGaN is poor so
transport of holes through GaN/AlGaN superlattices has been proposed and
investigated theoretically and experimentally with experimental results showing
poor transport. The reason for this poor performance is not fully understood.
In this paper, the transport of holes in GaN/AlGaN wurtzite crystal
superlattices is investigated through theoretical modeling, examining the role
of the composition of the Al$_x$Ga$_{1-x}$N barrier regions and the thickness
of the GaN quantum wells and the AlGaN barriers in determining the position and
width of the heavy hole miniband. To consider the transport of the holes in the
miniband we examine the effective mass of the miniband and possible scattering
mechanisms. In particular, ionized impurity(II) scattering from ionized
acceptors in the barrier regions is investigated as it is deemed to be the
dominating scattering mechanism degrading hole transport. The energy position
of the miniband relative to the ionized impurities and the wavefunction overlap
with the ionized acceptors in the barrier regions is investigated to minimize
II scattering. Some designs to optimize hole transport through wurtzite p-doped
GaN/AlGaN superlattices to minimize II scattering are proposed.
