石墨烯/PC_(6)/石墨烯异质结输运性质第一性原理研究

First-principles Study on the Transport Properties of Graphene/PC_(6)/Graphene Heterojunction

自石墨烯成功制备以来,二维碳基材料的研究受到了广泛关注,可期待克服硅基场效应管中出现的短沟道效应.采用密度泛函理论和非平衡态格林函数相结合的第一性原理方法,研究了石墨烯/PC_(6)/石墨烯异质结输运特性.研究发现金属的石墨烯与半导体的PC_(6)之间为肖特基接触,形成的势垒为0.15 eV.在非平衡态下,电流随电压增大,呈非线性增加特性.在较小的偏压下,可获得较大的开路电流.

Since the successful preparation of graphene,the study of two-dimensional carbon-based materials has received widespread attention and can be expected to overcome the short-channel effect that occurs in silicon-based field effect transistors.In this work,the graphene/PC_(6)/graphene heterojunction transport properties are investigated using a first-principles approach combining density-functional theory and non-equilibrium Green's function.It is found that the Schottky contact forms between metallic graphene and semiconducting,and the barrier is 0.15 eV.In the non-equilibrium state,the current increases nonlinearly with increasing voltage.A large open-circuit current is obtained at a small bias voltage.