  Electron transport in GaN/AlxGa1-xN superlattices is investigated using a
single particle Monte Carlo approach. To establish the band structure required
GaN, AlN and their ternary alloy are investigated using a single electron Monte
Carlo approach and a 3-band approximation to the full band structure. The
interplay of the inter-valley scattering and electron-longitudinal optical
polar phonon scattering in determining electron velocity and velocity overshoot
is examined for the binaries and their alloy. We use a Schrodinger wave
equation coupled to a Poisson solver to self-consistently calculate the energy
band structure of the superlattice using the single band approximation for the
materials, determine the Fermi energy and the superlattice miniband energy
position and its energy width. We then analyze the miniband band structure and
determine the effective masses for the superlattice miniband in the
superlattice direction which will determine the electron mobility in that
direction. Then the single particle Monte Carlo method is applied to
investigate electron transport in the miniband where we find that for low Al
concentration in the barrier and short periods electron velocity, very similar
to that in bulk GaN can be obtained and observe that velocity overshoot can
occur, purely due to electron-LO phonon scattering and non-parabolicity in the
single band. This modelling approach provides a fast and convenient method to
investigate high-field electron transport in n-doped GaN/Al$_x$Ga$_{1-x}$N
superlattices and should be suitable for use in device design.
