Shape and spatial correlation control of InAs-InAlAs-InP (001) nanostructure superlattices

Abstract

The control of shape and spatial correlation of InAs-InAlAs-InP(001) nanostructuresuperlattices has been realized by changing the As overpressure during the molecular-beam epitaxy (MBE) growth of InAs layers. InAs quantum wires (QWRs) are obtained under higher As overpressure (1×10⁻⁵Torr), while elongated InAsquantum dots(QDs) are formed under lower As overpressure (5×10⁻⁶ or 2.5×10⁻⁶Torr). Correspondingly, spatial correlation changes from vertical anti-correlation in QWR superlattices to vertical correlation in QDsuperlattices, which is well explained by the different alloy phase separation in InAlAs spacer layers triggered by the InAs nanostrcutures. It was observed that the alloy phase separation in QDsuperlattices could extend a long distance along the growth direction, indicating the vertical correlation of QDsuperlattices can be kept in a wide range of spacer layer thickness.