Excitation spectra of group III impurities in germanium under uniaxial stress

Abstract

The absorption spectra of Ga, In and Tl impurities in Ge have been measured using polarized radiation with uniaxial stress along the [100] and [111] crystallographic directions. The experimental lines have been identified using group theoretical selection rules and estimates of the polarized line intensities obtained from the acceptor state wave functions. From this identification the splittings of the acceptor ground state and the three excited states corresponding to the B, C and D lines have been determined. From the acceptor ground state splitting the splitting of the valence band edge in Ge and the corresponding deformation potential parameters can be obtained. The values determined are b=+0·9 ± 0·1 eV and d=+2·1 ± 0·2 eV.