Regensburg 2000 – scientific programme
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HL: Halbleiterphysik
HL 44: II-VI Halbleiter
HL 44.4: Talk
Friday, March 31, 2000, 11:15–11:30, H17
High-excitation properties and time-resolved behaviour of three-dimensional CdSe/ZnSe islands — •Martin Strassburg1, Axel Hoffmann1, Robert Heitz1, Udo W. Pohl1, Dieter Bimberg1, Dimitri Litvinov2, Andreas Rosenauer2, Dagmar Gerthsen2, Detlef Schikora3, and Klaus Lischka3 — 1Institut für Festkörperphysik, Technische Universität Berlin, 10623 Berlin, Germany — 2LEM der Universität Karlsruhe, 76128 Karlsruhe, Germany — 3Universität Paderborn, Fachbereich 6 Physik, 33098 Paderborn, Germany
Zero-dimensional excitons enable resonant gain as it was demonstrated for CdSe/ZnSe structures containing submonolayer islands only. In order to take advantage of the better thermal stability of islands grown in the Stranski-Krastanow (SK) mode, we have studied the gain in structures containing such islands. With an increase of the excitation density the high energy tail of the edge emission becomes broader and a shift of the emission maximum to higher energies by 20 meV occurs. We attribute the observed behaviour to a population of higher excited states. This explanation is supported by the results of gain investigations. Whereas at the threshold the gain maximum was observed in the resonance of the edge emission, an increase of the excitation density led to a strong blueshift of the gain maximum. The increase of the excitation density leads to a continuous rise of the maximum gain value up to 210 cm(−1) at 467 kW/cm2.