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HL: Halbleiterphysik

HL 45: II-VI Halbleiter II

HL 45.1: Talk

Friday, March 30, 2001, 11:30–11:45, S17

Reversible behaviour of Stranski-Krastanow grown CdSe islands — •Martin Bartels, Detlef Schikora, and Klaus Lischka — University of Paderborn, Department of Physics, D-33098 Paderborn, Germany

Quantum Dot (QD) structures based on II-VI compounds are of great interest for low threshold current laser diodes in the green spectral range. We report on studies about Stranski- Krastanow (SK) growth of CdSe coherently strained islands. Exposing the uncapped CdSe islands to a sulfure atmosphere, we observe a reproducible phase transition from a 3D-surface morphology to a flat 2D-surface. Time resolved reflection high energy electron diffraction (RHEED) intensity measurements reveal that the 3D character of the surface is maintained within 0-15 seconds and indicate a characteristic time period of about 30 seconds for a complete phase transition. We don’t observe the 3D-2D reversible transition for relaxed or partially relaxed CdSe layers. Photoluminescence measurements show a blueshift of the emission line in dependence of the exposure time.