Nguyen V Hung, Nguyen Huy-Viet, Dollfus P
L-Sim, SP2M, UMR-E CEA/UJF-Grenoble 1, INAC, F-38054 Grenoble, France. Center for Computational Physics, Institute of Physics, Vietnam Academy of Science and Technology, PO Box 429 Bo Ho, 10000 Hanoi, Vietnam.
Nanotechnology. 2014 Apr 25;25(16):165201. doi: 10.1088/0957-4484/25/16/165201. Epub 2014 Mar 26.
By means of numerical simulation, in this work we study the effects of uniaxial strain on the transport properties of strained graphene heterojunctions and explore the possibility of achieving good performance of graphene transistors using these hetero-channels. It is shown that a finite conduction gap can open in the strain junctions due to strain-induced deformation of the graphene bandstructure. These hetero-channels are then demonstrated to significantly improve the operation of graphene field-effect transistors (FETs). In particular, the ON/OFF current ratio can reach a value of over 10(5). In graphene normal FETs, the transconductance, although reduced compared to the case of unstrained devices, is still high, while good saturation of current can be obtained. This results in a high voltage gain and a high transition frequency of a few hundreds of GHz for a gate length of 80 nm. In graphene tunneling FETs, subthreshold swings lower than 30 mV /dec, strong nonlinear effects such as gate-controllable negative differential conductance, and current rectification are observed.
通过数值模拟，在本工作中我们研究了单轴应变对应变石墨烯异质结输运性质的影响，并探索了使用这些异质沟道实现高性能石墨烯晶体管的可能性。结果表明，由于应变引起的石墨烯能带结构变形，应变结中可以打开有限的导带隙。然后证明这些异质沟道能显著改善石墨烯场效应晶体管（FET）的性能。特别是，开/关电流比可以达到超过10⁵的值。在石墨烯普通FET中，跨导虽然比无应变器件的情况有所降低，但仍然很高，同时可以获得良好的电流饱和。对于80nm的栅长，这导致了高电压增益和几百GHz的高转换频率。在石墨烯隧穿FET中，观察到亚阈值摆幅低于30mV/dec，存在诸如栅极可控负微分电导和电流整流等强非线性效应。
