Confined phonon scattering in multivalley Monte Carlo simulation of quantum cascade lasers

Abstract

We present a detailed investigation of the effects that optical phonon confinement has on the electronic transport properties of GaAs-based multiple-quantum-well (MQW) quantum cascade laser (QCL) structures. Both confined and interface phonon modes are included based on the macroscopic dielectric continuum model. Interface phonon dispersions are obtained using the transfer matrix method with periodic boundary conditions. Scattering rates of both Γ- and X-valley electrons by all the interface and confined phonon modes are calculated and fully incorporated in the multivalley Monte Carlo simulation of a deep-active-well 6.7 μm GaAs-based MQW QCL. We find that the inclusion of phonon confinement enhances the electron-phonon scattering rates and output current to a relatively small extent with respect to the bulk phonon approximation.