1. Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8573, Japan
2. Device Technology Research Institute, AIST, 1-1-1 Umezono, Tsukuba 305-8568, Japan
3. Energy Process Research Institute, AIST, 16-1 Onogawa, Tsukuba 305-8569, Japan
4. Electron Microscope Facility, TIA, AIST, 1-2-1 Namiki, Tsukuba 305-8564, Japan
5. Global Zero Emission Research Center, AIST, 16-1 Onogawa, Tsukuba 305-8569, Japan