Spectral and temporal characteristics of emission from degenerate electron–hole plasma in GaAs and CdS at 300°K

Abstract

Investigations were made of the spectral and temporal characteristics of spontaneous and stimulated emission from a degenerate electron-hole plasma in GaAs and CdS excited by an electron beam having an energy of 150 keV and a pulse current of up to 650 A. The measurements were made at 300°K with a temporal resolution of ~10–11 sec. A study was made of the evolution kinetics of the radiation spectra as a function of the excitation rate. Determinations were made of the critical carrier densities at which the bound states were destroyed as a result of screening of the Coulomb interaction and the spectra became distorted: the narrow lines corresponding to carrier recombination via bound states disappeared and emission from the electron-hole plasma was observed. The carrier recombination times in the plasma were (0.3±0.1)×10–9 sec in GaAs and (1.4±0.3)×10–9 sec in CdS. The position on the energy scale and the shift of the plasma radiation spectra with increasing excitation level agreed with the theoretical concepts.