1. Department of Materials Science and Engineering, Chosun University, Gwangju 61452, Republic of Korea
2. Department of Materials Science and Engineering, Dankook University, Cheonan 31116, Republic of Korea
3. Department of Applied Physics, Aligarh Muslim University, Aligarh 202002, India
4. Micro & Nano Technologies, Inc., Gwangju 61452, Republic of Korea