Nanostructures formed on CdSe/ZnSe surfaces

Nanometer scale islands were observed in air on CdSe/ZnSe surfaces grown by molecular beam epitaxy. Measurements by atomic force microscope revealed t hat the aspect ratio of the island increased first and then decreased with time. Surface analyses by Auger electron spectroscopy indicated clearly tha t the island was composed in large part of oxides and the outer shell of th e island was Zn-enrichcd and Cd-depletcd. These islands showed sharp emissi ons as quantum dots. This work demonstrates that the islands were formed ma inly due to the oxidation of the surface and that it grew in a way similar to that generated from a strained film. III addition, intermixing of ZnSe a nd Zn segregation during the island Formation occurred. (C) 2001 Elsevier S cience B.V. All rights reserved.