Zhong Hongxia, Quhe Ruge, Wang Yangyang, Ni Zeyuan, Ye Meng, Song Zhigang, Pan Yuanyuan, Yang Jinbo, Yang Li, Lei Ming, Shi Junjie, Lu Jing
State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871, P. R. China.
State Key Laboratory of Information Photonics and Optical Communications &School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China.
Sci Rep. 2016 Mar 1;6:21786. doi: 10.1038/srep21786.
Although many prototype devices based on two-dimensional (2D) MoS2 have been fabricated and wafer scale growth of 2D MoS2 has been realized, the fundamental nature of 2D MoS2-metal contacts has not been well understood yet. We provide a comprehensive ab initio study of the interfacial properties of a series of monolayer (ML) and bilayer (BL) MoS2-metal contacts (metal = Sc, Ti, Ag, Pt, Ni, and Au). A comparison between the calculated and observed Schottky barrier heights (SBHs) suggests that many-electron effects are strongly suppressed in channel 2D MoS2 due to a charge transfer. The extensively adopted energy band calculation scheme fails to reproduce the observed SBHs in 2D MoS2-Sc interface. By contrast, an ab initio quantum transport device simulation better reproduces the observed SBH in 2D MoS2-Sc interface and highlights the importance of a higher level theoretical approach beyond the energy band calculation in the interface study. BL MoS2-metal contacts generally have a reduced SBH than ML MoS2-metal contacts due to the interlayer coupling and thus have a higher electron injection efficiency.
尽管已经制造出了许多基于二维（2D）二硫化钼（MoS2）的原型器件，并且实现了二维MoS2的晶圆级生长，但二维MoS2与金属接触的基本性质尚未得到很好的理解。我们对一系列单层（ML）和双层（BL）MoS2与金属接触（金属 = 钪（Sc）、钛（Ti）、银（Ag）、铂（Pt）、镍（Ni）和金（Au））的界面特性进行了全面的从头算研究。计算得到的和观察到的肖特基势垒高度（SBHs）之间的比较表明，由于电荷转移，多电子效应在沟道二维MoS2中受到强烈抑制。广泛采用的能带计算方案无法再现二维MoS2与Sc界面中观察到的SBHs。相比之下，从头算量子输运器件模拟能更好地再现二维MoS2与Sc界面中观察到的SBH，并突出了在界面研究中超越能带计算的更高层次理论方法的重要性。由于层间耦合，双层MoS2与金属接触的SBH通常比单层MoS2与金属接触的低，因此具有更高的电子注入效率。
