1. Faculty of Electrical Engineering and Computer Science,
Key Laboratory of Photoelectric Materials and Devices of Zhejiang
Province, Ningbo University, Zhejiang, 315211, China
2. Institute
of Physics, University of Muenster, Muenster 48149, Germany
3. Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
4. Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen 76344, Germany
5. Università degli Studi di Palermo, 90133 Palermo, Italy