Seung Hwan Lee, Min Sup Choi, Jia Lee, Chang Ho Ra, Xiaochi Liu, Euyheon Hwang, Jun Hee Choi, Jiangqiang Zhong, Wei Chen, and Won Jong Yoo, "High performance vertical tunneling diodes using graphene/hexagonal boron nitride/graphene hetero-structure", Applied Physics Letters 104, 053103, 2014.