1. Center for Integrated Smart Sensors (CISS), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
2. Convergence Materials & Parts Technology Research Center, Gumi Electronics & Information Technology Research Institute (GERI), Gumi 39171, South Korea
3. Department of Physics, Kongju National University, Gongju 32588, South Korea
4. National NanoFab Center (NNFC), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea