1. Photonics and Optoelectronics
Group,
Department of Physics and Center for NanoScience (CeNS), LMU München, Amalienstraße 54, Munich 80799, Germany
2. EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
3. Department of Chemistry, LMU München, Butenandtstraße
5-13 (E), 81377 Munich, Germany
4. Nanosystems Initiative Munich
(NIM), Schellingstraße 4, 80539 Munich, Germany