Kou Liangzhi, Frauenheim Thomas, Chen Changfeng
†Bremen Center for Computational Materials Science, University of Bremen, Am Falturm 1, 28359 Bremen, Germany.
‡Department of Physics and Astronomy and High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154, United States.
J Phys Chem Lett. 2013 May 16;4(10):1730-6. doi: 10.1021/jz400668d. Epub 2013 May 8.
Using density functional theory calculations, we unveil intriguing electronic properties of nanoscale multilayer transition-metal dichalcogenide (TMDC) heterostructures, (MoX2)n(MoY2)m (X, Y = S, Se or Te). Our results show that the structural stability and electronic band structure of the TMDC heterostructures depend sensitively on the choice of constituent components and their relative thickness. In particular, the electronic band gap can be tuned over a wide range by the intrinsic mismatch strain and spontaneous electrical polarization at the interface of the heterostructures, which suggests desirable design strategies for TMDC-based devices with an easily adjustable band gap. These interfacial effects also make the electronic properties more susceptible to the influence of a bias electric field, which can induce sensitive and considerable changes in the band gap and even produce a semiconductor-metal transition at relatively low electric fields. Such effective electronic band gap engineering via a combination of internal (i.e., the composition and layer thickness) and external (i.e., a bias field) control makes the TMDC-based heterostructures promising candidates for applications in a variety of nanodevices.
通过密度泛函理论计算，我们揭示了纳米级多层过渡金属二硫属化物（TMDC）异质结构（MoX2）n（MoY2）m（X、Y = S、Se或Te）引人入胜的电子特性。我们的结果表明，TMDC异质结构的结构稳定性和电子能带结构敏感地取决于组成成分的选择及其相对厚度。特别是，通过异质结构界面处的固有失配应变和自发电极化，可以在很宽的范围内调节电子带隙，这为具有易于调节带隙的基于TMDC的器件提出了理想的设计策略。这些界面效应还使电子特性更容易受到偏置电场的影响，偏置电场可在带隙中引起敏感且显著的变化，甚至在相对较低的电场下产生半导体-金属转变。通过内部（即组成和层厚度）和外部（即偏置场）控制相结合的这种有效的电子带隙工程，使得基于TMDC的异质结构成为各种纳米器件应用的有前途的候选者。
