EFFECT OF STRAIN ON VIBRATIONAL-MODES IN STRAINED-LAYER SUPERLATTICES

We have investigated the lattice vibrational properties of a two-component strained layer semiconductor superlattice (GaAs)n1 (GaSb)n2 using a one-dimensional linear chain model and transfer matrix method [1]. Effect of strain, arising due to the lattice mismatch (almost-equal-to 7%) has been considered explicitly in the equation of motion. We show for the first time that the optical vibrational frequency increases (in the case of (GaAs)4 (GaSb)n) or decreases (in the case of (GaAs)n(GaSb)4) with increase of layer thickness n, in either type of superlattices. Raman scattering measurements on some other similar systems support our findings.