Ngoc Thanh Thuy Tran works as a postdoctoral researcher at Center for Micro/Nano Science and Technology, National Cheng Kung University. Wen-Dung Hsu is Associate Professor, Department of Materials Science and Engineering, National Cheng Kung University. Jow-Lay Huang is Professor, Department of Materials Science and Engineering, National Cheng Kung University. Ming-Fa Lin is NCKU Distinguished Professor of Physics, National Cheng Kung University.