Far-Infrared Optical Properties of Quenched Germanium. IV. Uniaxial Stress Effects on the SA2 Acceptor

Abstract

Far-infrared absorption spectra of quenched germanium were measured under a uniaxial compressive force along the <100>, <110> and <111> crystallographic orientations. It has been concluded from analyses of the number of the bands split with stress and from the feature of the splitting of each band that the SA2 acceptor, which is one of the quenched-in acceptors and whose ground state is split into two levels without the external fields, is constructed from a defect whose symmetric axis is along the <111> crystallographic axis. The energy levels of the SA2 acceptor with stress are discussed; then, the deformation potential constants of the ground state of this acceptor and the valence band are estimated and are compared with those from about group-III-element acceptors.