1. Advanced Instrumentation Institute, Korea Research Institute of Standards and Science, Daejeon 34113, Republic of Korea
2. Department of Physics, Chonnam National University, Gwangju 61186, Republic of Korea
3. Precision Measurement, University of Science and Technology, Daejeon 34113, Republic of Korea
4. School of Materials Science and Engineering, Pusan National University, Busan 46241, Republic of Korea
5. Division of Electronics and Electrical Engineering, Dongguk University, Seoul 04620, Republic of Korea