Room temperature photoreflectance investigation of undoped and doped GaAs/AlGaAs quantum well structures

摘要

The room temperature photoreflectance (PR) investigation of optical transitions in Al_(0.2)Ga_(0.8)As/GaAs/Al_(0.2)Ga_(0.8)As single and coupled quantum wells is presented. The structures were grown by molecular beam epitaxy for different barrier thickness and quantum well width. Three kinds of spectral features were observed in PR spectra: sharp line connected with GaAs band gap (1.42 eV), Frantz-Keldysh oscillations near Al_(0.2)Ga_(0.8)As band gap (1.71 eV) and features originated from electron-hole transitions in quantum well. The energies of observed transitions have been compared with the results of envelope function calculations.