Charge transport gap in graphene antidot lattices
Charge transport gap in graphene antidot lattices
复制标题
DOI：
10.1103/physrevb.86.045445
复制
发表时间：
2012-07-26
影响因子：
3.7
通讯作者：
Kern, K.
中科院分区：
文献类型：
--
作者：
Giesbers, A. J. M.;Peters, E. C.;Kern, K.
石墨烯反点晶格（GAL）为石墨烯的带隙工程提供了一种有吸引力的方法。理论研究表明，开放间隙的大小对引入石墨烯片的纳米孔的形状、大小和结构敏感。我们已经研究了GAL的温度依赖性的电导率，包括50 nm直径的纳米孔与间距为80，100，和200 nm，分别。数据揭示了存在的局域态内的运输间隙，其相互作用导致软库仑间隙和相关的Efros-Shklovskii可变范围跳跃（ES-VRH）。这种传导类型在施加高达1特斯拉的磁场时被保留，在该磁场之上发生到莫特可变范围跳变的过渡。这种交叉可以替代地通过增加纳米孔间距或栅极控制的载流子浓度在零磁场下引入。此外，在中间磁场，跳跃指数假定值为2/3，在这种条件下，由ES-VRH的渗流理论预测。
Graphene antidot lattices (GALs) offer an attractive approach to band-gap engineering in graphene. Theoretical studies indicate that the size of the opened gap is sensitive to the shape, size, and architecture of the nanoholes introduced into the graphene sheet. We have investigated the temperature-dependent electrical conductivity of GALs comprising 50-nm-diameter nanoholes with a pitch of 80, 100, and 200 nm, respectively. The data reveal the presence of localized states within a transport gap, whose interactions lead to a soft Coulomb gap and associated Efros-Shklovskii variable range hopping (ES-VRH). This conduction type is preserved upon application of magnetic fields up to 1 Tesla, above which a transition to Mott variable range hopping occurs. Such a crossover can alternatively be introduced at zero magnetic fields by increasing either the nanohole spacing or the gate-controlled carrier concentration. Furthermore, at intermediate magnetic fields, the hopping exponent assumes a value of 2/3, as predicted by percolation theory for ES-VRH under this condition.