Luniov S. Influence of defective structure on the electrical and tensoelectrical properties of n-Ge and n-Si single crystals and film nanostructures based on them

The thesis is devoted to studying the regularities of influence of deformation, radiation, temperature fields and doping by the various impurities on the mechanisms of tensoeffects, electrical conductivity and scattering of current carriers in the n-Ge and n-Si single crystals and germanium nanofilms. Deformation potential constants and effective masses for Δ1-minimum of the germanium conduction band were found based on tensoresistance measurements of uniaxially deformed n-Ge single crystals along the crystallographic direction [100], theories of deformational potential and anisotropic scattering. Using these parameters allowed us to calculate the ionization energy of shallow donors Sb, As and P associated with the Δ1 – valleys, resistivity, Hall coefficient and electron mobility at high uniaxial pressures. The values of relative deformations, band structure and electrical properties for undoped and doped by the donor impurity of germanium nanofilm grown on the Ge(x)Si(1-x) (001) substrate, depending on its component composition were calculated. It was established that the quantum-dimensional effects significantly affect the electrical properties of the nanofilm with a thickness of d<7 nm. The mechanisms of defect formation were investigated and the nature of radiation defects in n-Ge<Sb> and n-Si<P> single crystals, irradiated by the high-energy electrons, was identified. A theoretical model of the annealing of point and complex defects in the electron-irradiated n-Ge<Sb> single crystals is proposed. The mechanisms of electrical conductivity and scattering of current carriers in undeformed and uniaxially deformed n-Ge and n-Si single crystals with technological and radiation defects, which create the deep energy levels in the band gap of germanium and silicon, were studied. It was established that the targeted impact of the electron irradiation and thermal annealing allows to an increase in the tenso, photo-, thermal and magnetic sensitivity of n-Ge and n-Si single crystals.