Transmission electron microscopy and photoluminescence characterization ofInAs quantum wires on vicinal GaAs(110) substrates by molecular beam epitaxy

InAs quantum wires have been naturally formed on vicinal GaAs(110) surfaces with giant steps by molecular beam epitaxy. Transmission electron microsco pe observations reveal the high density of stacking faults and the moire fr inge for thick wires (> 4 ML) due to the large InAs-GaAs lattice mismatch. From the moire fringe Separation, thick InAs wires are found to be complete ly relaxed. No defect is observed for thin wires (4 ML). Strongly polarized photoluminescence (PL) observed for InAs wires confirms the carrier confin ement to the quantum wire structures and the strain effect induced by the l arge lattice mismatch. A considerable energy shift is observed in the excit ation intensity dependence of FL, indicating large nonuniformity.