Das Tilak, Di Liberto Giovanni, Pacchioni Gianfranco
Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via Cozzi 55, Milano, 20125, Italy.
J Phys Condens Matter. 2022 Aug 3;34(40). doi: 10.1088/1361-648X/ac838b.
We investigated the impact of quantum confinement on the band gap of chalcogenides 2D nanostructures by means of density functional theory. We studied six different systems: MoS, WS, SnS, GaS, InSe, and HfSand we simulated nanosheets of increasing thickness, ranging from ultrathin films to ∼10-13 nm thick slabs, a size where the properties converge to the bulk. In some cases, the convergence of the band gap with slab thickness is rather slow, and sizeable deviations from the bulk value are still present with few nm-thick sheets. The results of the simulations were compared with the available experimental data, finding a quantitative agreement. The impact of quantum confinement can be rationalized in terms of effective masses of electrons and holes and system's size. These results show the possibility of reliably describing quantum confinement effects on systems for which experimental data are not available.
我们通过密度泛函理论研究了量子限制对硫族化物二维纳米结构带隙的影响。我们研究了六个不同的体系：MoS、WS、SnS、GaS、InSe和HfS，并且模拟了厚度不断增加的纳米片，从超薄膜到厚度约为10 - 13纳米的平板，在这个尺寸下其性质趋近于体相。在某些情况下，带隙随平板厚度的收敛相当缓慢，对于几纳米厚的薄片，与体相值仍存在相当大的偏差。模拟结果与现有的实验数据进行了比较，发现了定量的一致性。量子限制的影响可以根据电子和空穴的有效质量以及体系尺寸来进行合理解释。这些结果表明，对于尚无实验数据的体系，可靠描述量子限制效应是可能的。
