Dai Tian-Jun, Xiao Xiang, Fan Zhong-Yuan, Zhang Zi-Yan, Zhou Yi, Xu Yong-Chi, Sun Jian, Liu Xue-Fei
School of Electronic Information Engineering, Guiyang University, Guiyang 550005, China.
School of Physics and Electronic Science, Guizhou Normal University, Guiyang 550025, China.
Nanomaterials (Basel). 2025 Jul 3;15(13):1035. doi: 10.3390/nano15131035.
Fermi-level pinning (FLP) at metal-semiconductor interfaces remains a key obstacle to achieving low-resistance contacts in two-dimensional (2D) transition metal dichalcogenide (TMDC)-based heterostructures. Here, we present a first-principles study of Schottky barrier formation in WSe-MoSe van der Waals heterostructures interfaced with four representative metals (Ag, Al, Au, and Pt). It was found that all metal-WSe/MoSe direct contacts induce pronounced metal-induced gap states (MIGSs), leading to significant FLP inside the WSe/MoSe band gaps and elevated Schottky barrier heights (SBHs) greater than 0.31 eV. By introducing a 2D metal-doped metallic (mWSe/mMoSe) layer between WSe/MoSe and the metal electrodes, the MIGSs can be effectively suppressed, resulting in nearly negligible SBHs for both electrons and holes, with even an SBH of 0 eV observed in the Ag-AgMoSe-MoSe contact, thereby enabling quasi-Ohmic contact behavior. Our results offer a universal and practical strategy to mitigate FLP and achieve high-performance TMDC-based electronic devices with ultralow contact resistance.
金属-半导体界面处的费米能级钉扎（FLP）仍然是在基于二维（2D）过渡金属二硫属化物（TMDC）的异质结构中实现低电阻接触的关键障碍。在此，我们对与四种代表性金属（Ag、Al、Au和Pt）界面的WSe-MoSe范德华异质结构中肖特基势垒的形成进行了第一性原理研究。结果发现，所有金属-WSe/MoSe直接接触都会诱导出明显的金属诱导能隙态（MIGSs），导致WSe/MoSe带隙内出现显著的FLP，并使肖特基势垒高度（SBHs）升高至大于0.31 eV。通过在WSe/MoSe与金属电极之间引入二维金属掺杂金属（mWSe/mMoSe）层，可以有效抑制MIGSs，使电子和空穴的SBHs几乎可以忽略不计，在Ag-AgMoSe-MoSe接触中甚至观察到0 eV的SBH，从而实现准欧姆接触行为。我们的结果提供了一种通用且实用的策略，以减轻FLP并实现具有超低接触电阻的高性能基于TMDC的电子器件。
