Shen Tao, Ren Ji-Chang, Liu Xinyi, Li Shuang, Liu Wei
Nano and Heterogeneous Materials Center, School of Materials Science and Engineering , Nanjing University of Science and Technology , Nanjing 210094 , China.
J Am Chem Soc. 2019 Feb 20;141(7):3110-3115. doi: 10.1021/jacs.8b12212. Epub 2019 Feb 8.
Incorporation of two-dimensional (2D) materials in electronic devices inevitably involves contact with metals, and the nature of this contact (Ohmic and/or Schottky) can dramatically affect the electronic properties of the assembly. Controlling these properties to reliably form low-resistance Ohmic contact remains a great challenge due to the strong Fermi level pinning (FLP) effect at the interface. Herein, we employ density functional theory calculations to show that van der Waals stacking can significantly modulate Schottky barrier heights in the contact formed between multilayer InSe and 2D metals by suppressing the FLP effect. Importantly, the increase of InSe layer number induces a transition from Schottky to Ohmic contact, which is attributed to the decrease of the conduction band minimum and rise of the valence band maximum of InSe. Based on the computed tunneling and Schottky barriers, CdC is the most compatible electrode for 2D InSe among the materials studied. This work illustrates a straightforward method for developing more effective InSe-based 2D electronic nanodevices.
在电子器件中引入二维（2D）材料不可避免地涉及与金属的接触，而这种接触的性质（欧姆接触和/或肖特基接触）会极大地影响组件的电子性能。由于界面处强烈的费米能级钉扎（FLP）效应，控制这些性能以可靠地形成低电阻欧姆接触仍然是一个巨大的挑战。在此，我们采用密度泛函理论计算表明，范德华堆叠可以通过抑制FLP效应显著调节多层InSe与二维金属之间形成的接触中的肖特基势垒高度。重要的是，InSe层数的增加会导致从肖特基接触向欧姆接触的转变，这归因于InSe导带最小值的降低和价带最大值的升高。基于计算出的隧穿和肖特基势垒，在研究的材料中，CdC是二维InSe最兼容的电极。这项工作说明了一种开发更有效的基于InSe的二维电子纳米器件的直接方法。
