INTERFERENCE EFFECTS IN REFLECTANCE LINE-SHAPES FROM ZNSE GAAS EPILAYERS/

The reflectance spectroscopy is performed at 77 K on ZnSe epilayers of different thicknesses grown on GaAs substrates. The exciton line shap es of the reflectance spectra change dramatically with the epilayer th ickness. This observation suggests that the interference effects betwe en the reflected waves from the surface and from the interface play an important role on the exciton line shape of the reflectance spectra. To analyze the change in the exciton line shapes quantitatively, the r eflectance spectra were calculated using a simple oscillator model for a dielectric function and considering a multiple reflection. Calculat ed line shapes of the reflectance spectra show good agreement with the observations. (C) 1998 Elsevier Science Ltd. All rights reserved.