Wang Bing, Niu Xianghong, Ouyang Yixin, Zhou Qionghua, Wang Jinlan
School of Physics, Southeast University , Nanjing 211189, China.
Synergetic Innovation Center for Quantum Effects and Applications (SICQEA), Hunan Normal University , Changsha 410081, China.
J Phys Chem Lett. 2018 Feb 1;9(3):487-490. doi: 10.1021/acs.jpclett.7b03036. Epub 2018 Jan 16.
High carrier mobility and moderate band gap are two key properties of electronic device applications. Two ultrathin two-dimensional (2D) semiconductors, namely, BiTeS and BiTeSe nanosheets, with novel electronic and optical properties are predicted based on first-principles calculations. The BiTeS and BiTeSe monolayers own moderate band gaps (∼0.7 eV) and high electron mobilities (∼20 000 cm V s), and they can absorb sunlight efficiently through the whole incident solar spectrum. Meanwhile, layer-dependent exponential decay band gaps are also unveiled. The relatively low interlayer binding energies suggest that these monolayers can be easily exfoliated from bulk structures. Their high dynamical and thermal stabilities are further verified by phonon dispersion calculations and ab initio molecular dynamics simulations. The exceptional properties render BiTeX (X = S, Se) monolayers promising candidates in future high-speed (opto)electronic devices.
高载流子迁移率和适中的带隙是电子器件应用的两个关键特性。基于第一性原理计算预测了两种具有新颖电子和光学性质的超薄二维（2D）半导体，即BiTeS和BiTeSe纳米片。BiTeS和BiTeSe单层具有适中的带隙（约0.7 eV）和高电子迁移率（约20000 cm² V⁻¹ s⁻¹），并且它们可以在整个入射太阳光谱范围内有效地吸收太阳光。同时，还揭示了与层数相关的指数衰减带隙。相对较低的层间结合能表明这些单层可以很容易地从块状结构中剥离出来。通过声子色散计算和从头算分子动力学模拟进一步验证了它们的高动力学稳定性和热稳定性。这些优异的特性使BiTeX（X = S，Se）单层成为未来高速（光）电子器件中有前景的候选材料。
