Relationship between carrier mobility and bandgap in low- dimensional carbon materials

The intact graphene has a zero bandgap and subsequent low on-off ratio, while modifications on graphene to open the bandgap always bring about dramatic reduction of mobility. Therefore, how to build a graphene device performing both large on-off ratio and high carrier mobility is one of the most attractive topics. Herein, we investigated the intrinsic mobility of graphene-related systems theoretically. A ubiquitous linear dependence of the effective mass on bandgap was demonstrated to cause the inverse mobility-gap relationship in graphene. Moreover, the deformation-potential constant E1, which also affects the mobility greatly, was found to be determined by both bandgap and the strain dependence of Fermi energy [1]. An effective tailoring of E1 is essential for pursuing high mobility in graphenerelated systems. Based on this, we further found that some specific boron-nitride-embedded graphene had low E1 and mobility comparable to that of graphene when its bandgap is nonzero. And their transport polarities (whether electron or hole transport dominates) could be tailored by strain. Our results indicate that this hybrid material is promising for transistor devices [2].