NEW APPROACH TO THE FABRICATION OF CDSE ZNSE QUANTUM DOTS USING A CLEAVED-EDGE OVERGROWTH TECHNIQUE/

Spontaneous formation of CdSe/ZnSe quantum dots (QDs) in ultra high va cuum (UHV) by molecular beam epitaxy (MBE) was investigated using clea vage-induced GaAs (110) surfaces as substrates. Stranski-Krastanow (S- K)-type CdSe QDs were randomly distributed on the atomically flat surf ace. On the other hand, QD structures were abnormally formed at the ma croscopic steps produced by the cleaving process of the substrates. Th ese QDs were naturally arranged along the edge of the steps. Microscop ic photoluminescence (PL) spectra of the QDs at step regions showed a few number of sharp peaks originating from the individual QDs. Therefo re, the cleaved edge overgrowth technique is a novel method for fabric ation of isolated CdSe QDs which is useful to investigate optical prop erties of individual QD structures. (C) 1998 Elsevier Science B.V. All rights reserved.