Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin , Austin, Texas 78758, United States.
National Institute for Material Science , 1-1Namiki, Tsukuba, Ibaraki 305-0044, Japan.
Nano Lett. 2016 Aug 10;16(8):4975-81. doi: 10.1021/acs.nanolett.6b01646. Epub 2016 Jul 20.
Interlayer tunnel field-effect transistors based on graphene and hexagonal boron nitride (hBN) have recently attracted much interest for their potential as beyond-CMOS devices. Using a recently developed method for fabricating rotationally aligned two-dimensional heterostructures, we show experimental results for devices with varying thicknesses and stacking order of the graphene electrode layers and also model the current-voltage behavior. We show that an increase in the graphene layer thickness results in narrower resonance. However, due to a simultaneous increase in the number of sub-bands and decrease of sub-band separation with an increase in thickness, the negative differential resistance peaks becomes less prominent and do not appear for certain conditions at room temperature. Also, we show that due to the unique band structure of odd number of layer Bernal-stacked graphene, the number of closely spaced resonance conditions increase, causing interference between neighboring resonance peaks. Although this can be avoided with even number of layer graphene, we find that in this case the bandgap opening present at high biases tend to broaden the resonance peaks.
基于石墨烯和六方氮化硼（hBN）的层间隧道场效应晶体管因其作为超越 CMOS 器件的潜力而引起了广泛关注。利用最近开发的制备旋转对准二维异质结构的方法，我们展示了不同厚度和堆叠顺序的石墨烯电极层的器件的实验结果，并对电流-电压行为进行了建模。我们发现，随着石墨烯层厚度的增加，共振会变窄。然而，由于厚度增加导致子带数量增加，同时子带间隔减小，负微分电阻峰变得不那么明显，并且在某些条件下在室温下不会出现。此外，我们还表明，由于奇数层 Bernal 堆叠石墨烯的独特能带结构，接近的共振条件数量增加，导致相邻共振峰之间的干扰。尽管偶数层石墨烯可以避免这种情况，但我们发现，在这种情况下，高偏压下存在的带隙开口往往会使共振峰变宽。
