石墨烯纳米结构中负微分电阻效应研究

Study on negative differential resistance in graphene nanostructures

由于石墨烯具有高电子迁移率的特性,可以用来制备高频电子器件。利用传输矩阵方法,对石墨烯p-n结及方形势垒纳米结构中的负微分电阻效应进行了研究。证实了石墨烯p-n结中负微分电阻现象比传统半导体中的幅度要小,石墨烯中Klein隧穿过程的存在使负能量范围内的空穴对电流产生影响。石墨烯纳米方形势垒中发生负微分电阻效应的位置在费米面附近,势垒宽度越大,对载流子的阻挡越大,负微分电阻效应越明显。

The negative differential resistance(NDR)effect of graphene in the p-n junctions and nanoscale barriers is investigated by using transfer-matrix method.The NDR phenomenon in the graphene p-n junctions is not so obvious as that in the conventional semiconductors,because the holes in the negative energy range also contribute to the current due to the Klein tunneling.The NDR location of graphene nanoscale barriers lies on the Fermi energy level.The block of the barrier to the current is more apparent with increasing barrier width,and the NDR effect becomes more obvious.