Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 47: Quantum Hall Effect

HL 47.1: Vortrag

Mittwoch, 9. März 2016, 09:30–09:45, H14

Impact of the dynamically tuned 2DEG density on the photoluminescence of modulation-doped CdTe and CdMnTe quantum wells — •Janina Rautert¹, Dion Braukmann¹, Jörg Debus¹, Vitalii Yu. Ivanov², Dmitri R. Yakovlev^1,3, Grzegorz Karczewski², Tomasz Wojtowicz², and Manfred Bayer^1,3 — ¹Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany — ²Institute of Physics, Polish Academy of Sciences, 02668 Warsaw, Poland — ³Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia

A highly concentrated two-dimensional electron gas (2DEG) in a modulation-doped semiconductor quantum well (MDQW) shows many interesting features in both transport measurements and optical spectroscopy, like the integer and fractional quantum Hall effect (QHE). It is known that the formation of trion and exciton complexes in a MDQW strongly depends on the 2DEG density, which can be controlled by the laser power and its energy as well as by an external magnetic field. We study the competition between the 2DEG and negative trion photoluminescence (PL) in the stationary and time-resolved regime (showing up for several hundreds of µ s) for a CdTe MDQW at different magnetic fields. By comparison, in a CdMnTe MDQW the exciton magneto-PL shows variations in the energy for transitions between different QHE regimes at elevated temperatures above 1.5 K. Moreover, the 2DEG and exciton PL lines may anticross at different points of time with increasing magnetic field.