OPTICAL-PROPERTIES OF EXCITONS IN SEMICONDUCTOR QUANTUM-WELLS

Oscillator strength of excitons in various quantum wells is systematically investigated analyzing Fourier transform reflectance spectra. The temperature dependence of the oscillator strength of the zero-phonon line transition is well described by a modified Debye-Waller expression with an averaged phonon mode. This allows us to investigate the exciton-phonon interaction. The oscillator strength in GaAs/AlGaAs quantum wells increases as the well width is reduced in agreement with the existing theory, while in InGaAs/GaAs and GaAs/GaAsP quantum wells takes a maximum at a certain well width, showing the variation from two- to three-dimensional characters. The oscillator strength in InGaAs/GaAs and GaAs/GaAsP quantum wells is differently dependent on the alloy composition variation.