1. The Institute of Scientific and Industrial Research (ISIR-SANKEN), Osaka University, Osaka 567-0047, Japan
2. Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8565, Japan
3. Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
4. Global Innovation Center (GIC), Kyushu University, Fukuoka 816-8580, Japan
5. Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
6. Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
7. Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka 816-8580, Japan
8. Department of Applied Physics, Aalto University, P.O. Box 11100, 00076 Aalto, Finland