Temperature-dependent valence band offset and band-gap energies of pseudomorphic GaAsSb on GaAs

The band-gap (E-gp) and valence band offset (DeltaE(v)) energies of pseudom orphic GaAsSb layers on GaAs substrate are determined from temperature-depe ndent photoluminescence measurements on GaAsSb/GaAs and GaAsSb/GaAlAs quant um wells grown by molecular beam epitaxy. A clear evidence of staggered typ e-II band alignment of GaAsSb relative to GaAs and a value of 1.05 for the valence band offset ratio (Q(v)) are proposed. Finally, through a detailed comparison of these values with those published previously, we have shown t hat the scatter in Q(v) found in the literature (<1 to 2.1) is closely depe ndent on the exact determination of E-gp. Particularly, we have shown that the strain dependence of the deformation potential is important in the calc ulation of the strain energy contribution to E-gp. (C) 2001 American Instit ute of Physics.