Raman scattering study of [hhk]-GaAs/(Si or CaF2) strained heterostructures

Abstract
Raman spectroscopy is used to measure the frequency shift, symmetry, and activity of long-wavelength optical phonons in several GaAs strained epilayers. The results are compared with theoretical evaluations using the elastic compliances, phonon deformation potentials, and Raman tensors. The effect of growth direction ([001], [111], and [112]) and the substrate nature (Si or CaF2) is analyzed. The importance of nonstandard growth directions, [111] or [112], on residual stress and piezoelectric effect is discussed.