Berlin 2015 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 95: Poster IV B (Quantum dots and wires: Prepration, characterization, optical properties, and transport)
HL 95.12: Poster
Donnerstag, 19. März 2015, 14:00–20:00, Poster B
Pressure-induced shift of energy levels and structural phase transition in CdSe/ZnS quantum dots — Jonas Tauch1, •Johannes M. Braun2, Janine Keller1, Christopher Hinz1, Johannes Haase1, Denis V. Seletskiy1, Alfred Leitenstorfer1, and Alexej Pashkin1,2 — 1Department of Physics and Center for Applied Photonics, University of Konstanz, Germany — 2Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
Electronic band structure of CdSe/ZnS quantum dots under high pressures is studied using fluorescence spectroscopy. We observe a strong blue shift of about 40 meV/GPa for the emission line at 655 nm. At moderate pressures (below 3 GPa) this shift is linear and it is dominated by increase of the fundamental band gap of CdSe under pressure [1,2]. In contrast to bulk CdSe where the fluorescence is quenched above 3 GPa as a result of the phase transition into the rock-salt structure [3,4], the CdSe/ZnS quantum dots remain structurally stable up to 6.5 GPa. This structural robustness together with the high fluorescence yield and the large pressure-induced line shift, exceeding that of bulk ruby crystals by a factor of 40, make CdSe quantum dots a promising candidate for precise pressure calibration at moderate pressures.
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