Electron Mobility and Energy Relaxation Rate in GaAs/GaAlAs Superlattice

摘要

Electron mobility in GaAs/Ga_(0.7)Al_(0.3)As superlattice is calculated theoretically taking into account longitudinal optic (lo) phonon emission of both bulk and superlattice types. Our model is based on the effective mass concept for the electrons and the dispersive continuum model for the lo phonons. The solutions of the Schrodinger equation for the electrons are matched at the interfaces by the usual requirement of continuity of probability and current densities. Bloch's theory is used to incorporate the superlattice periodicity along the growth axis. The lo phonons are treated by the dispersive hydrodynamic continuum model. Electron - phonon coupled interactions for both bulk and superlattice phonons has been considered. From the knowledge of the inter subband electron transition rates and capture rates for various well widths, electron mobility in the superlattice is calculated. The variation of mobility with well width for both bulk and superlattice phonons has been shown. Energy relaxation rate for the electrons has been calculated and its variation with well width is also exhibited for both bulk and superlattice phonons