Stacking-fault-induced pairs of localizing centers in ZnSe quantum wells

Pairs of bright spots are observed in microphotoluminescence intensity maps of ZnSe/ZnMgSSe quantum-well structures. These pairs are exactly aligned p arallel to the [110] or [(1) over bar 10] directions. Atomic-force microsco py and plan-view transmission electron microscopy reveal that the bright em ission spots are related to pairs of stacking faults. The enhanced radiativ e recombination is a result of exciton localization in the region where the stacking faults intersect the quantum wells. Cross-section transmission el ectron microscopy and microphotoluminescence spectroscopy show that in the case of Frank-type stacking faults (oriented along [110]) the wells are enl arged by up to 12 bilayers. The exciton localization is much shallower in t he case of Shockley-type stacking-fault pairs (oriented along [(1) over bar 10]). (C) 2000 Elsevier Science B.V. All rights reserved.