Role of contacts in graphene transistors: A scanning photocurrent study
Role of contacts in graphene transistors: A scanning photocurrent study
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DOI：
10.1103/physrevb.79.245430
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发表时间：
2009-06-01
影响因子：
3.7
通讯作者：
Avouris, Ph.
中科院分区：
文献类型：
--
作者：
Mueller, T.;Xia, F.;Avouris, Ph.
利用近场扫描光学显微镜在高空间分辨率的石墨烯晶体管中局部感应光电流。通过分析空间分辨光响应，我们发现，在n型传导区，由于金属触点掺杂石墨烯，沿石墨烯器件形成了p-n-p结构。电子结构的修改不仅限于金属电极下方，而且延伸到石墨烯通道内0.2-0.3 μ m。根据这种光电成像方法获得的电位分布，讨论了石墨烯晶体管中常见的电子和空穴的不对称传导行为。此外，我们证明光电流成像可以用于探测单层/多层石墨烯界面。
A near-field scanning optical microscope is used to locally induce photocurrent in a graphene transistor with high spatial resolution. By analyzing the spatially resolved photoresponse, we find that in the n-type conduction regime a p-n-p structure forms along the graphene device due to the doping of the graphene by the metal contacts. The modification of the electronic structure is not limited only underneath the metal electrodes but extends 0.2-0.3 mu m into the graphene channel. The asymmetric conduction behavior of electrons and holes that is commonly observed in graphene transistors is discussed in light of the potential profiles obtained from this photocurrent-imaging approach. Furthermore, we show that photocurrent imaging can be used to probe single-layer/multilayer graphene interfaces.