1. Semiconductor Device Research Laboratory, Department of Electrical Engineering, Faculty of Engineering, Chulalongkorn University, 254 Phayathai Road, Bangkok 10330, Thailand
2. Synchrotron Light Research Institute (Public Organization), Ministry of Science and Technology, Nakhon Ratchasima 30000, Thailand
3. National Metal and Materials Technology Center, Thailand Science Park, 114 Paholyothin Rd., Klong 1, Klong Luang, Pathumthani 12120, Thailand