1. Division of Solid State Physics and NanoLund, Lund University, P.O. Box 118, SE-22100 Lund, Sweden
2. Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Winterbergstrasse 28, 01277 Dresden, Germany
3. Institute of Semiconductors and Microsystems, Technische Universität Dresden, D-01062 Dresden, Germany
4. Department of Electronics and Nanoengineering, Micronova, Aalto University, P.O. Box 13500, FI-00076 Aalto, Finland