Regensburg 2007 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 46: Poster 2
HL 46.38: Poster
Thursday, March 29, 2007, 15:00–17:30, Poster A
Optical Spectroscopy on Metastable Zincblende MnCrS/ZnSe Heterostructures — •Limei Chen1, Wolfram Heimbrodt1, Peter Jens Klar2, Lorraine David3, Christine Bradford3, and Kevin Prior3 — 1Department of Physics and Material Sciences Center, Philipps-University Marburg, Germany — 2I. Institute of Physics, Justus-Liebig-University Giessen, Germany — 3School of Engineering and Physical Sciences, Heriot-Watt university, Edinburgh, UK
A series of zinkblende MnS/ZnSe heterostructures with varying thickness from 1.8 to 8.6nm and a series of MnCrS/ZnSe heterostructures with different Cr contents up to 50% were grown by molecular beam epitaxy on (100) GaAs substrates with a growth temperature of 240∘C. The optical properties of the heterostructures were studied using time-resolved photoluminescence spectroscopy with time scales from microseconds to milliseconds at low temperature(10K). The photoluminescence is dominated by the 4T1 to 6A1 internal transition of the Mn2+ (3d5) cations at 590 nm. The decay times of the internal luminescence of MnS layers show only a weak size dependence and do not vary when using different excitation energies, i.e. 355 nm (3.49 eV) exciting above the ZnSe band gap or 532 nm (2.33 eV) excitation exciting directly into the Mn 3d5 absorption but below the ZnSe and MnS band gaps. The decay times of the MnCrS layers show no clear size and Cr concentration dependence and are faster than those of the Cr-free MnS layers indicating an energy transfer from the Mn 3d-shell to Cr internal transitions.