Generalized multilayer model for the quantitative analysis of the electromodulation components of the electroreflectance and photoreflectance spectra of semiconductors in the region of the E 0 fundamental transition

Abstract

With the assumption of the Franz-Keldysh effect as the origination mechanism of the interband electromodulation E0 component, a generalized multilayer model of this effect was proposed. This model includes such physical parameters as the strength of the surface electric field and its decay profile in the space charge region, energy broadening, and partial modulation of the surface electric field. It was shown that the three regions can be defined in the simulated spectra, namely, the low-energy region, the region of main peak, and the high-energy region of the Franz-Keldysh oscillations. The effect of the model parameters on the line shape in these regions was studied. The ranges of the actual parameters were determined from the quantitative analysis of the experimental photoreflectance spectra of GaAs and InP substrates (n=1015 cm−3–1018 cm−3).