Shape and spatial correlation control of InAs-InAlAs-InP „001... nanostructure superlattices

The control of shape and spatial correlation of InAs-InAlAs-InP 001 nanostructure superlattices 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 10−5 Torr , while elongated InAs quantum dots QDs are formed under lower As overpressure 5 10−6 or 2.5 10−6 Torr . Correspondingly, spatial correlation changes from vertical anti-correlation in QWR superlattices to vertical correlation in QD superlattices, 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 QD superlattices could extend a long distance along the growth direction, indicating the vertical correlation of QD superlattices can be kept in a wide range of spacer layer thickness. © 2006 American Institute of Physics. DOI: 10.1063/1.2172288