Femtosecond Relaxation of Photoexcited Nonequilibrium Carriers inAlxGa1xAs

Abstract
Optical saturation of highly excited states in the conduction band of a semiconductor and the subsequent extremely fast energy relaxation due to carrier-carrier and opticalphonon scattering at room temperature are observed. The corresponding measured life-time for states 160 meV above the band edge in Al0.34 Ga0.66 As is in the range of 80 to 30 fs depending upon the photoexcited carrier density.