1. Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP), Technische Universität Dresden, 01069 Dresden, Germany.
2. Leibnitz Institute for Solid State and Materials Research, IFW, Helmholtzstraße 20, 01069 Dresden, Germany.
3. Technische Universität München, Department of Chemistry, Lichtenbergstr. 4, 85748 Garching b. München, Germany.
4. Center for Advancing Electronics Dresden (cfaed), Technische Universität Dresden, Helmholtz Str. 18, 01069 Dresden, Germany.
5. CNR-SPIN Institute, Corso F. M. Perrone 24, 16152 Genova, Italy.