1. Department of Materials Science and Engineering; National Taiwan University No. 1, Sec. 4; Roosevelt Road Taipei 10617 Taiwan
2. Department of Materials Science and Engineering; National Cheng-Kung University; Tainan 701 Taiwan
3. Department of Physics and Astronomy; University of New Mexico; Albuquerque, NM 87131 USA
4. Department of Chemical and Materials Engineering; National University of Kaohsiung, Kaohsiung 81148, Taiwan Department 700; Kaohsiung University Rd., Nan-Tzu District Kaohsiung 811 Taiwan) ectronic
5. Department of Materials Science and Engineering; I-Shou University; Kaohsiung 840 Taiwan