Molecular Dynamics Simulation of Transport in Diamond and GaN: Role of Collective Excitations

Abstract

ABSTRACTIn this paper we consider the role of collective excitations in transport of charge carriers in the conduction band of diamond and GaN. The present molecular dynamics simulation uses a Monte Carlo algorithm to determine the time between collisions with scattering rates calculated quantum mechanically using the Fermi Golden Rule. For very thin films (L=0.01 μm) and for low fields (F<10 V/μm), the energy spectra of both diamond and GaN contain a series of peaks which are attributed to the absorption and emission of discrete plasmons. In diamond. the intervalley LA, LO and TO scattering becomes increasingly more important at higher fields while electron-plasmon interactions decrease. For thicker diamond films (L=0.1 μm), there is hot electron transport for F∼10 V/μm and quasi-ballistic transport for F-100 V/μm. In GaN with L=0.01 μm and fields F∼10 V/μm, there is a discrete series of peaks in the energy spectrum corresponding to excitations associated with polar optical scattering.