The formation process of self-assembled CdSe quantum dots below critical thickness

The formation process of CdSe self-assembled quantum dots (SAQDs) below the critical thickness was observed by atomic force microscopy (AFM) for the f irst time. Two monolayers (MLs) of CdSe coverage were grown directly on GaA s (1 0 0) surfaces by metalorganic chemical vapor deposition (MOCVD). AFM i mages were taken constantly of the same area of 1 mum(2) within several hou rs after the growth. It revealed that the formation of CdSe SAQDs under cri tical thickness was due to the effect of surface diffusion and strain relea se. Our results make it possible to directly observe the process of release strain and to obtain the actual information on the formation process of se lf-assembled quantum dots. (C) 2000 Elsevier Science B.V. All rights reserv ed.