How Do Contact and Channel Contribute to the Dirac Points in Graphene Field-Effect Transistors?
How Do Contact and Channel Contribute to the Dirac Points in Graphene Field-Effect Transistors?
复制标题
接触和沟道如何影响石墨烯场效应晶体管中的狄拉克点？
DOI：
10.1002/aelm.201800158
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发表时间：
2018-08-01
影响因子：
6.2
通讯作者：
Yu, Guanghui
中科院分区：
文献类型：
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作者：
Peng, Song-ang;Jin, Zhi;Yu, Guanghui
石墨烯场效应晶体管（GFET）中的狄拉克点对于电子应用是非常重要的。然而，缺乏有效的手段来区分石墨烯在接触区和沟道区的电学性质，限制了对它们对狄拉克点的贡献的清晰理解。分别建立了金属接触下和沟道中石墨烯电学性质的表征方法。研究发现，石墨烯在沟道区和接触区的费米能级在GFET中有很大的不同。费米能级的差异导致接触下的掺杂效应渗透到长达1 μ m的沟道中。这种差异还导致长沟道GFET中的双狄拉克点特征，这是由于接触和沟道中的组合石墨烯性质。短沟道GFET中的两个狄拉克点之一由于接触下掺杂效应的渗透而减小。研究表明，短沟道GFET的电学行为主要由接触区决定。这为深入理解和进一步通过控制整个器件的费米能级来提高GFET的性能提供了一条途径。
The Dirac point(s) in graphene field-effect transistors (GFETs) are of great importance for electronic application. However, the lack of the effective means to distinguish the electrical properties of graphene at the contact and channel regions limits a clear understanding of their contributions to the Dirac point(s). A method, which can characterize the electrical properties of graphene under metal contact and in the channel, is developed, respectively. It is found that the Fermi levels of graphene at the contact and channel regions are quite different in the GFETs. The difference in Fermi levels results in the penetration of the doping effect under the contact into the channel with a length as long as 1 mu m. The difference also causes the double Dirac point feature in the long-channel GFET due to the combined graphene properties both in contact and channel. One of the two Dirac points diminished in short-channel GFET due to the penetration of doping effect under the contact. The study demonstrates that the electrical behavior of short-channel GFET is dominated by the contact region. This paces a way to deeply understand and further improve the performances of GFETs by controlling the Fermi levels in the whole devices.