Investigação da piezoresistência causada pela redistribuição de electrões entre L1 e ∆1 mínimos do germânio

Abstract

The aim of this work is to investigate the phenomenon of piezoresistance in n-Ge single crystals, in the presence of uniaxial elastic deformation (DEU) along the crystallographic axis of type [001]. A bibliographical investigation was carried out, which allowed us to clarify the main causes of the appearance of piezoresistance in classical semiconductor single crystals, with many minima on the constant energy surface, methods of measuring piezoresistance and practical application of this effect. The Herring-Smith piezoresist is differentiated from that caused by GED along the [001] axis. Calculations are carried out to analyze in detail the displacement kinetics of the energy minima in the presence of DEU and investigate the Li<->Aj minima inversion. Analytical expressions were obtained for calculating the fill numbers, which describe the redistribution of electrons between the different groups of energy minima as a function of pressure and temperature. The theory of anisotropic scattering was used, which allowed to obtain and numerically analyze expressions for the electrical conductivity tensor and the electrical resistivity tensor of n-Ge single crystals in the presence of DEU, taking into account minimum Lt and Ai. The results of numerical calculations of electrical resistivity, taking into account that electrons are scattered only by acoustic phonons, are in good qualitative agreement with the experimental data.(TRADUÇÃO NOSSA)