1. Department of Materials Science and Engineering and Frederick Seitz Materials Research Laboratory; University of Illinois at Urbana-Champaign; Urbana IL 61801 USA
2. Department of Mechanical Engineering; University of Houston; Houston TX 77204 USA
3. Department of Electronic Materials Engineering; The Australian National University; Canberra ACT 0200 Australia
4. Department of Chemistry; The Catholic University of Korea; Yokkok, Bucheon, Kyunggi 420-743 Korea
5. Department of Electrical Engineering; The Pennsylvania State University; University Park PA 16802 USA
6. Department of Physics; College of Sciences; China University of Mining and Technology; Xuzhou Jiangsu 221116 PR China