Highly luminescent ZnSe quantum dot arrays (QDAs) are spontaneously formed on cleavage-induced GaAs (110) surfaces. The QDAs are configured for their preferred growth on the step top. The confinement on carriers results from the difference in the band gaps of the strained ZnSe layer and the strain-relaxed ZnSe QDA. In contrast to other emissions from the ZnSe layer, the linewidth of the QDA emission is dependent neither on temperature nor on excitation intensity. Moreover, the energy position of the QDA emission is stable even at high excitations. These results reflect the δ functionlike density of states of the QDAs. This letter suggests a novel approach to semiconductor QDs and QDAs.
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