InAs self-organized quantum dashes grown on GaAs (211)B

We have grown InAs self-organized quantum dots and quantum dashes on GnAs (211)B substrates by molecular beam epitaxy. The growth temperature dependence of InAs nanostructures were studied by in situ reflection high-energy electron diffraction (RHEED) and es situ atomic force microscopy. In the studied temperature range from 400 to 510 degrees C, the RHEED pattern changed from streaky to spotty after deposition of 6 ML of InAs, showing the formation of nanostructures. The quantum dots grown at lower growth temperatures (from 400 to 490 degrees C) showed bimodal dot size distribution. At higher growth temperatures, a drastic change from quantum dots to quantum dashes was observed. The quantum dashes have an asymmetric hutlike shape and align themselves along the [01(1) over bar] direction. The quantum dash width increases dramatically, whereas the average length and density increases slightly on further deposition of InAs. (C) 1997 American Institute of Physics.