1. Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand;
2. Faculty of Education, Suratthani Rajabhat University, Suratthani, Thailand;
3. PhD Degree Program in Applied Physics, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand;
4. Faculty of Science and Agricultural Technology, Rajamangala University of Technology Lanna, Chiang Mai, Thailand