1. College of Nanotechnology, King Mongkut’s Institute of Technology Ladkrabang, Ladkrabang, Bangkok 10520, Thailand
2. Thailand Center of Excellence in Physics, Commission on Higher Education, Ministry of Education, Bangkok 10400, Thailand
3. National Electronics and Computer Technology Center, National Scienceand Technology Development Agency, Patumthani 12120, Thailand
4. National Nanotechnology Center, National Science and Technology Development Agency, Patumthani 12120, Thailand
5. ImPACT Research Center for Advanced Nanobiodevices, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan