Hz. Wu et al., OBSERVATION OF HOT-ELECTRON RELAXATION IN GAAS ALGAAS MULTIPLE-QUANTUM WELLS BY EXCITATION SPECTROSCOPY/, Journal of vacuum science & technology. B, Microelectronics and nanometer structures processing, measurement and phenomena, 15(4), 1997, pp. 849-853
Hot electron relaxation in GaAs/AlGaAs multiple quantum well (MQW) str
ucture was studied with the use of photoluminescence excitation (PLE)
spectroscopy. Oscillation due to the emission of confined longitudinal
optical (LO) GaAs phonons, by photoexcited electrons were observed in
the (6 K) excitation spectra. The period of the oscillation is differ
ent from that observed in bulk GaAs. The calculation from a four-band
Kane model, describing the mixing of heavy-and light-hole bands at wav
e vector away from k=0, was used to interpret the difference of oscill
ation features between the GaAs/AlGaAs MQW structure and bulk GaAs. Th
e recorded PLE spectrum and calculated results show that photoexcited
electrons can directly cascade downwards to the exciton energy state b
y LO phonon emissions. (C) 1997 American Vacuum Society.