He Zhonglin, Ma Yandong, Lei Chengan, Peng Rui, Huang Baibiao, Dai Ying
School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China.
J Chem Phys. 2020 Feb 21;152(7):074703. doi: 10.1063/1.5141053.
Two-dimensional van der Waals heterostructures (vdWHs) with tunable band alignment can be very useful for developing minimized multifunctional and controllable devices, but so far they are scarcely reported. Here, using first-principles calculations, we systematically investigate the electronic properties of TlO/WTe vdWH. Our results indicate that it is a direct bandgap semiconductor harboring a straddling type-I band alignment, with the conduction band minimum (CBM) and valence band maximum (VBM) both from two-dimensional WTe. Interestingly, upon introducing feasible external strain or electric field, its band alignment can be easily transformed into staggered type-II, with CBM and VBM separated in different layers, achieving the long-sought tunable multiple band alignments. Along with this, the intriguing direct-to-indirect bandgap transition is also achieved in TlO/WTe vdWH. Our work thus provides a promising candidate in the field of two-dimensional multifunctional and controllable electronics.
具有可调节能带排列的二维范德华异质结构（vdWHs）对于开发小型化多功能和可控器件非常有用，但迄今为止鲜有报道。在此，我们使用第一性原理计算系统地研究了TlO/WTe vdWH的电子性质。我们的结果表明，它是一种具有跨立型I型能带排列的直接带隙半导体，其导带最小值（CBM）和价带最大值（VBM）均来自二维WTe。有趣的是，在引入可行的外部应变或电场后，其能带排列可轻松转变为交错型II型，CBM和VBM位于不同层中，实现了长期以来寻求的可调谐多能带排列。与此同时，在TlO/WTe vdWH中还实现了有趣的直接到间接带隙转变。因此，我们的工作为二维多功能和可控电子学领域提供了一个有前景的候选材料。
