Affiliation: | 1. Institute for Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany;2. DFG-Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany;3. Department of Materials Science and Opto-electronic Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan, ROC;4. Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), 763131 Karlsruhe, Germany |