Raman phonon piezospectroscopy in GaAs: Infrared measurements

Abstract

Earlier Raman piezospectroscopic measurements for GaAs, performed with visible radiation, suggest that uniaxial stresses may be as much as 30% smaller at the surface than in the bulk of the material. We present here measurements in the forward-, backward-, and 90\ifmmode^\circ\else\textdegree\fi{}-scattering configurations performed with a cw Nd-YAG (YAG denotes yttrium aluminum garnet) laser to which GaAs is transparent. We confirm the above suggestion and obtain accurate values for the deformation potentials of LO and TO phonons. We also obtain the dependence of the effective charge on uniaxial strain and compare it with recent theoretical calculations. Phenomena related to plastic deformations are observed at the highest stresses attained.