Growth of self-assembled (Zn)CdSe nanostructures on ZnSe by migration enhanced epitaxy

The growth of CdSe on ZnSe by migration enhanced epitaxy has been studied i n situ by means of reflection high-energy electron diffraction (RHEED) and reflection anisotropy spectroscopy (RAS). The change from a streaky to a sp otty RHEED pattern during CdSe deposition indicates the transition to a thr ee-dimensional growth mode. This change is accompanied by a damping of RHEE D intensity oscillations and a decrease in the overall intensity. RAS spect ra show a pronounced change at a photon energy of about 2.2 eV with increas ing CdSe thickness. To investigate the role of lattice mismatch, ternary Zn CdSe layers of different compositions have been grown. With decreasing Cd c oncentration the critical thickness for the growth mode transition increase s and for Cd concentrations below 30% no growth mode transition could be ob served. (C) All 1999 Elsevier Science B.V. All rights reserved.