Influence of Amplified Spontaneous Emission on Energy Relaxation, Recombination and Ultrafast Expansion of Hot Carriers in Direct-Gap Semiconductors

摘要: The picosecond cooling and spatial expansion dynamics of high density ( > 1018 cm−3) photoexcited plasmas in direct gap semiconductors has commanded much attention over the past twenty years. However one aspect plasma evolution that often been ignored is role amplified spontaneous emission (ASE). common belief radiative recombination occurs on a nanosecond time scale therefore unimportant for dynamics. Nonetheless, which becomes degenerate as it cools, optical gain can occur ASE induce reheating scale, slowing down process. This regimes where hot phonon effects1 have previously surmised to be major factor determining reduced rate. In addition, lead an effective ultrafast carrier diffusion2,3 through transfer. Overall, initially generated certain volume with above critical value, we find strong nonlocal behavior whereby temperature depend position well excitation volume. To illustrate this present here results simulations GaAs 1-D geometry, appropriate many lasers or induced-grating experiments. Similar effects are expected 2- 3-D.