Pei Xin, Hu Xiaohui, Xu Tao, Sun Litao
College of Materials Science and Engineering, Nanjing Tech University, Nanjing 211816, China.
Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Nanjing Tech University, Nanjing 211816, China.
Nanomaterials (Basel). 2024 Jun 24;14(13):1075. doi: 10.3390/nano14131075.
The contact resistance formed between MoS and metal electrodes plays a key role in MoS-based electronic devices. The Schottky barrier height (SBH) is a crucial parameter for determining the contact resistance. However, the SBH is difficult to modulate because of the strong Fermi-level pinning (FLP) at MoS-metal interfaces. Here, we investigate the FLP effect and the contact types of monolayer and multilayer MoS-metal van der Waals (vdW) interfaces using density functional theory (DFT) calculations based on Perdew-Burke-Ernzerhof (PBE) level. It has been demonstrated that, compared with monolayer MoS-metal close interfaces, the FLP effect can be significantly reduced in monolayer MoS-metal vdW interfaces. Furthermore, as the layer number of MoS increases from 1L to 4L, the FLP effect is first weakened and then increased, which can be attributed to the charge redistribution at the MoS-metal and MoS-MoS interfaces. In addition, the p-type Schottky contact can be achieved in 1L-4L MoS-Pt, 3L MoS-Au, and 2L-3L MoS-Pd vdW interfaces, which is useful for realizing complementary metal oxide semiconductor (CMOS) logic circuits. These findings indicated that the FLP and contact types can be effectively modulated at MoS-metal vdW interfaces by selecting the layer number of MoS.
MoS与金属电极之间形成的接触电阻在基于MoS的电子器件中起着关键作用。肖特基势垒高度（SBH）是决定接触电阻的关键参数。然而，由于MoS-金属界面处强烈的费米能级钉扎（FLP），SBH难以调制。在此，我们基于Perdew-Burke-Ernzerhof（PBE）水平，使用密度泛函理论（DFT）计算研究了单层和多层MoS-金属范德华（vdW）界面的FLP效应和接触类型。结果表明，与单层MoS-金属紧密界面相比，单层MoS-金属vdW界面中的FLP效应可显著降低。此外，随着MoS层数从1L增加到4L，FLP效应先减弱后增强，这可归因于MoS-金属和MoS-MoS界面处的电荷重新分布。此外，在1L-4L MoS-Pt、3L MoS-Au和2L-3L MoS-Pd vdW界面中可实现p型肖特基接触，这对于实现互补金属氧化物半导体（CMOS）逻辑电路很有用。这些发现表明，通过选择MoS的层数，可以在MoS-金属vdW界面有效地调制FLP和接触类型。
