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

Abstract
The band-gap (E gp ) and valence band offset (ΔE v ) energies of pseudomorphic GaAsSb layers on GaAs substrate are determined from temperature-dependentphotoluminescencemeasurements on GaAsSb/GaAs and GaAsSb/GaAlAs quantum wellsgrown by molecular beam epitaxy. A clear evidence of staggered type-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 that the scatter in Q v found in the literature (<1 to 2.1) is closely dependent on the exact determination of E gp . Particularly, we have shown that the strain dependence of the deformation potential is important in the calculation of the strain energy contribution to E gp .