Ordering of stacked InAs/GaAs quantum-wires in InAlAs/InGaAs matrix on (1 0 0) InP substrates

Stacked and wire-like InAs/GaAs nanostructures in InGaAs/InAlAs matrix on InP substrates were grown by molecular beam epitaxy (MBE) and investigated by atomic force microscope (AFM) and transmission electron microscope (TEM). Cross-sectional TEM images showed that the stacked InAs and GaAs quantum-wires in InGaAs matrix were vertically aligned to form a rectangular lattice. In contrast, in InAlAs matrix, the stacked InAs quantum-wires were cross-correlated to form a bcc like lattice. Clear composition modulation was observed in the post-grown matrix material. Based on this result, a kinetic growth model is proposed to explain the stacking behavior of the quantum-wires.