Investigation of Be doped GaSb with varying hole concentrations using single magnetic field Hall measurement and Raman spectroscopy

Abstract

Raman scattering results on Beryllium doped Gallium antimonide (GaSb) epi-layers with varying hole concentrations (3 × 1017 cm−3 to 5 × 1019 cm−3) are presented in this study. The hole concentrations are determined from single magnetic field Hall measurements and corrected taking into consideration two band conduction. The Raman spectra show four distinct features: Longitudinal optical (LO) phonon mode from the surface accumulation/depletion region, disorder activated forbidden transverse optical (TO) phonon mode, LO phonon coupled Plasmon (LOPC) mode and the uncoupled LO phonon mode from the bulk region. A detailed Raman line-shape analysis using deformation potential and electro-optic contribution has been carried out to reproduce the experimental results. The effect of plasmon damping on the LO phonon coupled Plasmon (LOPC) mode is discussed. Free hole concentrations are derived from the Raman line-shape analysis and compared with that from the Hall measurements.