Analysis of Sb-As surface exchange reaction in molecular beam epitaxy of GaSb/GaAs quantum wells

GaSb/GaAs quantum wells (QWs) were grown on the GaAs(001)substrate by molecular beam epitaxy (MBE), and their QW structures were analyzed using a kinetic model that takes into account the surface exchange reaction of As and Sb atoms during GaAs cap growth. The photoluminescence peak energy of GaSb/GaAs QWs depended on the growth temperature of the GaAs cap layer, and this dependence was explained by a broadening of the QW structure, due to the As-Sb exchange reaction. The calculated optical transition energy of the analyzed QW structure almost agreed with experimental results after adjusting the bowing parameter (b(v)) for the valence band edge in GaAs1-xSbx alloys and the activation energy of the Sb-As surface exchange reaction (E-Sb, E-As). As the result, b(v) = 0.67 +/- 0.06, E-Sb 1.68 +/- 0.01 eV and E-As = 1.80 +/- 0.01 eV were obtained.