1. Fachbereich Physik, CHyN, Universität Hamburg, 22761 Hamburg, Germany
2. Fachbereich Physik, Philipps-Universität Marburg, Renthof 5, 35032 Marburg, Germany
3. Biosystems Technology, Institute of Life Sciences and Biomedical Technologies, Technical University of Applied Sciences Wildau, Hochschulring 1, 15745 Wildau, Germany
4. Department of Microelectronics, Nankai University, 300350 Tianjin, China