Gentsar P. "Electron effects in electroreflectance spectra of subsurface layers in materials of the fourth and AIII BV groups"

The thesis is devoted to the investigation of effects of interband phototunneling and filling the bands in spectra of electroreflectance of germanium, features of electron phenomena in heavily doped solid solutions of Ge - Si, GaAs and GaP in the range of the fundamental absorption edge. Developed is the method of separation of surface and bulk components in electroreflectance. Obtained are data upon the contribution of the Friedel screen oscillations into the capacity of polycrystalline n-Ge1-xSix solid solutions with the bulk electron concentration close to 1026 m-3 and presence of high (approximately 2.108 V.m-1) built-in electric field in a thin (~2 nm) subsurface region of Ge1-xSix . A linear variation of m with the solution composition x is found. The relation between the charge carrier mobility and collision parameter of broadening the optical spectra in assumption of independency between scattering processes for the photogenerated electron and hole as well as the relation between periods of the Keldysh-Franz oscillations )Em and electron parameters of subsurface layers are ascertained.