Raman study of GaAs-In<i>x</i>Al1−<i>x</i> As strained-layer superlattices

Abstract

Raman spectroscopy has been used to study the lattice-mismatch strains in GaAs-InxAl1−xAs strained-layer superlattices grown by molecular beam epitaxy with the layer thicknesses of 10–200 Å and In content x of 0.11, 0.20, and 0.35. The strain-induced shifts of the longitudinal optic phonon modes indicate that the GaAs and InxAl1−xAs layers have the tensile and compressive strains, respectively, along the interfaces. The strain calculated from the observed frequency shift agrees with the lattice-mismatch strain given by the elastic theory.