单层石墨烯多势垒结构中的输运及能谱特性

Transport properties and energy spectrum with multi-barriers in monolayer graphene

利用传递矩阵的方法研究了单层石墨烯中势垒个数N=1、3、5、7、9、11时,等高方形势垒和对称的阶跃势垒结构中电子的隧穿几率和电导.通过周期性势垒中的能带结构对载流子隧穿特性进行分析.结果表明,在多势垒结构中,仍存在Klein隧穿效应.单层石墨烯的隧穿几率和电导依赖于势垒高度、势垒宽度、入射能量和入射角度,还受到势垒形状的影响.能带结构中显示有能级分布的区域表明势垒和势阱间载流子状态匹配,出现隧穿共振,在载流子隧穿谱中对应地体现.相应的在多势垒结构中,可以通过调节势垒结构参数来控制单层石墨烯的电导.

With the transfer matrix method, the transmission coefficient and the conductance in monolayer graphene were investigated in the presence of the same height square-barrier structures and the symmetrical step-barrier structures with 1, 3, 5, 7, 9, 11 barriers respectively. The cartier tunneling properties could be analyzed through the energy band structure in the periodic barrier structure. The results indicated that Klein tunneling effect still existed in the multi-barrier structure systems. The transmission coefficient and the conductance depended on the barrier height, barrier width, incident energy, incident angle and barrier shape. The distribution area in the energy spectrum structure indicated the existing state matching well at the interface of barrier, which corresponded to the resonant tunneling. Accordingly, in the multi-barrier structure systems the conductance can be adjusted by the parameters of the barrier structure in monolayer graphene.