1. Department of Materials Science and Engineering; National Chiao Tung University; 1001 University Road Hsinchu Taiwan 30010, Taiwan (R.O.C.)
2. Institute of Lighting and Energy Photonics; National Chiao Tung University; Taiwan
3. National Synchrotron Radiation Research Center; Hsinchu 30076 Taiwan
4. National Nano Device Laboratories; National Applied Research Laboratories; Hsinchu 300 Taiwan
5. Materials and Chemistry Laboratories; Industrial Technology Research Institute; Hsinchu City, 300 Taiwan (R.O.C.)