1. Research Institute of Electronics; Shizuoka University; 3-5-1 Johoku, Naka-ku Hamamatsu 432-8011 Japan
2. Department of Physics; International Christian University; 3-10-2 Osawa, Mitaka Tokyo 181-8585 Japan
3. Nanomaterials Research Institute; National Institute of Advanced Industrial Science and Technology; 1-1-1 Higashi Tsukuba 305-8565 Japan
4. Department of Materials Science & Engineering; National University of Singapore; 7 Engineering Drive 1 117574 Singapore