Determination of GaAsSb/GaAs heterojunction band offset by photoluminescence spectroscopy

Photoluminescence spectroscopy was observed for a set of Al/sub 0.5/Ga0.5As/Al/sub x/Ga/sub 1-x/As/GaAs/sub 0.643/Sb/sub 0.357//Al/sub x/ Ga/sub 1-x/As/Al/sub 0.5/Ga/sub 0.5/As 5-layer quantum wells with different Al mole fraction x (different conduction band barrier heights E/sub x/= E/sub c/(Al/sub x/Ga/sub 1-x/As) - E/sub c/(GaAs)). The theoretical calculation and the data fitting for the experimental data show the conduction band offset of GaAs/sub 0.643/Sb/sub 0.357//GaAs heterojunction is almost flat (weak type I), /spl Delta/E/sub c/ = E/sub c/(GaAs) - E/sub c/(GaAsSb) = 13 /spl plusmn/ 13 meV and the bandgap bowing parameter for strained GaAsSb is -1.58 /spl plusmn/ 0.01 eV.