1. School of Physics, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
2. School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
3. National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani 12120, Thailand