PHOTOREFLECTANCE LINESHAPE ANALYSIS OF THE SELECTIVELY-DOPED GAAS AL0.3GA0.7AS MICROSTRUCTURE/

The photoreflectance spectra of the selectively-doped GaAs/Al0.3Ga0.7A s microstructure have been studied at various temperatures. The spectr a contained two sets of oscillatory features above the gap of GaAs, an d one set above the gap of Al0.3Ga0.7As. The sources of different feat ures in the spectra were identified by comparing the spectra after dif ferent layers were etched off. The magnitudes of the internal fields w ere obtained from the band bendings near the surface or interfaces. A multilayer model with a different electric field in each layer was use d to take into account the depth dependence of the dielectric function s due to different materials and the electric fields in the space-char ge regions. The calculated lineshapes agree well with the observed pho ton modulated reflectance spectra.