1. School of Electrical Engineering; Graphene/2D Materials Research Center; Korea Advanced Institute of Science and Technology (KAIST); Daejeon 34141 South Korea
2. Department of Mechanical Engineering; Graphene/2D Materials Research Center; Korea Advanced Institute of Science and Technology (KAIST); Daejeon 34141 South Korea
3. Electronics and Telecommunications Research Institute; Daejeon 34129 South Korea