COPPER-RELATED DEFECTS IN IN0.53GA0.47AS GROWN BY LIQUID-PHASE EPITAXY

High-purity In0.53Ga0.47As lattice matched to InP was grown by liquid-phase epitaxy and used for the study of Cu-related defects. The samples had a free-electron carrier concentration of n = 5.0 X 10(14) cm-3 and an electron mobility of mu77 K = 44 000 cm2/V s. A Cu-related acceptor level 25 meV above the valence-band edge was identified using photoluminescence measurements. Comparing the energy position of this shallow acceptor level with the E(v) + 157.8-meV Cu-acceptor level in GaAs supports the assumption of an internal energy reference level [J. M. Langer, C. Delerue, M. Lannoo, and H. Heinrich, Phys. Rev. B38, 7723 (1988)] common to GaAs and InxGa1-xAs.