Complemental theory for vertical transport in semiconductor superlattices

In a superlattice, it is known that localized electronic states are formed due to an electric field applied along the growth axis. Therefore, an electron changes its nature from a wave to a particle. Such a change of electronic nature imposes on us to apply different frameworks of transport theory depending on the strength of electric field. In this paper, we show that such a complemental nature of electrons can be described in a unified way by considering electronic acceleration during a scattering event. Based on the unified picture and by means of the Monte Carlo simulation, we calculate drift velocities of electrons in a superlattice. Crossover between band-transport in low fields and hopping-transport in high fields is studied and discussed.