Dresden 2003 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 49: Poster II
HL 49.66: Poster
Donnerstag, 27. März 2003, 16:30–19:00, HSZ/P2
Metastable Exciton States in ZnCdSe Quantum Wells with Nanoislands — •Alexander Reznitsky1,2, Albert Klochikhin1,2, Benedicte Dal Don1, Heiko Priller1, Heinz Kalt1, Claus Klingshirn1, Irina Sedova2, Dimitri Litvinov3, and Dagmar Gerthsen3 — 1Institut für Angewandte Physik, Universität Karlsruhe (TH) — 2Ioffe Physical-Technical Institute RAS, St.-Petersburg, Russia — 3Laboratorium für Elektronenmikroskopie, Universität Karlsruhe (TH)
The optical spectra of MBE-grown ZnCdSe quantum wells with nanoislands formed by CdSe insertions in ZnSe have been studied. For all samples, the temperature dependence of the photoluminescence (PL) band maximum follows either a "normal" or an "anomalous" (i.e. "S-shaped") dependence. We consider both dependences in detail and argue that anomalous behavior is caused by metastable exciton states originating from the complex spatial shape of the islands. It was found that these states influence the shape of low temperature PL spectra under cw excitation below the mobility edge [1] or at the early decay stage under pulse excitation. The interplay between metastable and ground exciton states in an island with increasing temperature is responsible for the anomalous temperature dependence of the PL band maximum. We have shown that the number of metastable states in island and their role in the radiative recombination can be affected by an variation of growth parameters.
[1] A.Reznitsky, et.al.,phys.stat.sol.(b) 229, 509 (2002).