Graphene/hBN vertical transistor : tuning a tunneling barrier height by modulating fermi energy level of graphene

Graphene is a 2-dimensional plane of carbon and a zero-band gap material whose conduction and valence band meet at dirac point. This electronic band structure makes it possible that the graphene's fermi energy level is modulated with accumulated charges by ~0.5 eV [1]. In this study, the unique property of graphene, large modulation of fermi energy level, was used to realize a vertical transistor which is based on graphene/hexagonal boron nitride (hBN) heterostructure. This device controlled tunneling barrier height between graphene and hBN by modulating the graphene's fermi energy level, and I_on/I_off up to 10⁶ was achieved at 300 K. We also confirmed that there was little change in performance of device at 300 K and 15 K.

[1] I. Gierz et al., Nano Lett. 8, 12 (2008).