1. School of Physics, Suranaree University of Technology, 111 University Avenue, Nakhon Ratchasima 30000, Thailand
2. Department of Physics, Burapha University, 169 Long-Hard Bangsaen Road, Chonburi 20131, Thailand
3. School of Physics, Suranaree University of Technology, 111 University Avenue, Nakhon, Ratchasima 30000, Thailand