Regensburg 2007 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 25: Quantum dots and wires: Optical properties II

HL 25.3: Talk

Tuesday, March 27, 2007, 14:30–14:45, H17

Optically detected resonance studies of diluted magnetic semiconductor quantum dots — •Michael Gerbracht¹, Gregor Bartsch¹, Piotr Wojnar², Dmitri Yakovlev¹, Ulrike Woggon¹, Jacek Kossut², and Manfred Bayer¹ — ¹Experimentelle Physik II, Universität Dortmund, Otto-Hahn-Str. 4, D-44227 Dortmund, Germany — ²Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa, Poland

Diluted magnetic semiconductor quantum dots (Cd,Mn)Te/ZnTe grown by molecular-beam epitaxy have been studied by optically detected resonance (ODR) technique in magnetic fields up to 15 T. The photoluminescence (PL) of samples has been measured with and without additional illumination of far infrared (FIR) radiation with photon energies of 7.6, 10.5 and 12.8 meV. Strong changes of the excitonic photoluminescence induced by FIR radiation have been found at magnetic fields below 1T. Measurements performed for different FIR energies, various temperatures and for samples with different Mn contents varied from 0 up to 4% allow us to conclude that the ODR signal is caused by heating of the spin system of magnetic Mn ions. Also the competition of intrinsic and exchange contributions to the Zeeman splitting of excitonic states have been recognized as a decrease of the Zeeman splitting at high magnetic fields.