1. College of Nanotechnology, King Mongkut's Institute of Technology Ladkrabang, Chalongkrung Rd., Ladkrabang, Bangkok, 10520, Thailand
2. Thailand Center of Excellence in Physics, CHE, 328 Si Ayutthaya Rd., Bangkok 10400, Thailand
3. Nanotec-KMITL Center of Excellence on Nanoelectronic Devices, Chalongkrung Rd., Ladkrabang, Bangkok 10520, Thailand