1. H. Maeda, Y. Deguchi, R. Takanabe, S. Matsuda, T. Kato, Proc. of the SiC and Related Materials Researches 20th Conference, pp.137-138 (2011).
2. K. Hotta, K. Kawata, M. Nagaya, T. Kido, T. Kato, Proc. of the SiC and Related Materials Researches 20th Conference, pp.141-142 (2011).