INAS SELF-ORGANIZED QUANTUM DASHES GROWN ON GAAS (211)B

We have grown InAs self-organized quantum dots and quantum dashes on G nAs (211)B substrates by molecular beam epitaxy. The growth temperatur e dependence of InAs nanostructures were studied by in situ reflection high-energy electron diffraction (RHEED) and es situ atomic force mic roscopy. In the studied temperature range from 400 to 510 degrees C, t he 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 drasti c change from quantum dots to quantum dashes was observed. The quantum dashes have an asymmetric hutlike shape and align themselves along th e [01(1) over bar] direction. The quantum dash width increases dramati cally, whereas the average length and density increases slightly on fu rther deposition of InAs. (C) 1997 American Institute of Physics.