Formation of CdSe nanoclusters in MgO by ion beam synthesis

Embedded CdSe nanoclusters were created in MgO by ion implantation of I x 10(16) Cd and 1 x 10(16) Se ions cm(-2) at an energy of 280 and 210 keV, respectively, and subsequent thermal annealing at 1300 K. Transmission electron microscopy analysis shows that the smallest nanoclusters with sizes below 5 nm adopt a rock salt crystal structure and that the orientation relationship with the rock salt MgO is cube-on-cube. The larger nanoclusters have a different crystal structure that is sphalerite or wurtzite CdSe. The defect evolution during the annealing procedure is investigated by means of optical absorption spectroscopy and Doppler broadening positron beam analysis. (C) 2003 Elsevier B.V. All rights reserved.