Uniformity enhancement of the self-organized InAs quantum dots

Growth interruption was introduced after the deposition of GaAs cap layer, which is thinner than the height of quantum dots. Uniformity of quantum dot s has been enhanced because the full-width of half-maximum of photoluminesc ence decrease from 80 to 27 meV in these samples as the interruption time i s increased. Meanwhile, we have observed that the peak position of photolum inescence is a function of interruption time, which can be used to modulate energy level of quantum dots. All of the phenomenon mentioned above can be attributed to the diffusion of In atoms from the tops of InAs islands to t he top of GaAs cap layer caused by the difference between the surface energ ies of InAs and GaAs. (C) 1999 Elsevier Science B.V. All rights reserved.