Dynamics of Photo-Excited Carriers and Coherent Effects in GaN Under Subpicosecond Laser Pulse Excitation

摘要

We applied the Semiconductor Bloch Equations formalism to study the subpicosecond dynamics of photo-excited carriers in gallium nitride (GaN). The kinetics equations were derived using a two-band model and taking into account the coherent interaction of semiconductor with the short laser pulse. Various scattering terms due to interaction of carriers with polar optical phonons and carrier-carrier interaction were taken into account. Effects of the conduction band nonparabolicity and static screening were included in our theory. We find reasonable agreement with the experimental results on the time-resolved photoluminescence rise-time dependence on excitation energy and carrier density, thus confirming the dominant role of polar optical phonons in the subpicosecond dynamics, and the effects of screening.