探索对 MoS2 激子性质和电子能带结构的量子限制效应,Applied Surface Science

当前位置： X-MOL 学术 › Appl. Surf. Sci. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

探索对 MoS2 激子性质和电子能带结构的量子限制效应
Applied Surface Science ( IF 6.3 ) Pub Date : 2020-07-01 , DOI: 10.1016/j.apsusc.2020.146262
Xudan Zhu , Dahai Li , Rongjun Zhang , Hao Zhang , Chunxiao Cong , Meiping Zhu , Yuejie Shi , Yu Wu , Songyou Wang , Yuxiang Zheng , Liangyao Chen

摘要我们通过光谱椭偏仪系统地研究了量子限制对厘米级 MoS2 薄膜（层数：N = 1、2、4 和 18）的激子性质和电子能带结构的影响。包括光导率、激子结合能和临界点 (CP) 在内的光学特性被追踪为层数的函数。我们发现与多层 MoS2 中的值相比，A 和 B 激子在单层 MoS2 中具有最大的结合能，因为前者没有层间耦合。尽管如此，即使层数发生变化，A 和 B 激子的峰值位置几乎相同。这是因为抵消了准粒子带隙和激子结合能之间的差异。此外，计算八个CP的阈值能量；使用这些值，可以确定 CP 的价带和导带排列。值得注意的是，当层数超过四层时，MoS2 的电子能带结构变得稳定，这可以归因于在这些情况下大大减弱的量子限制效应。我们的研究结果帮助我们更好地了解量子限制对使用 MoS2 薄膜的光电和光伏应用的影响。

"点击查看英文标题和摘要"

Probing Quantum Confinement Effects on the Excitonic Property and Electronic Band Structures of MoS2

Abstract We systemically investigate the effects of quantum confinement on the excitonic property and electronic band structures of centimeter-scale MoS2 films (number of layers: N = 1, 2, 4, and 18) through spectroscopic ellipsometry. The optical properties including optical conductivity, exciton binding energy and critical points (CPs) are traced as a function of layer number. We find that A and B excitons have the largest binding energies in monolayer MoS2 compared with the values in multilayer MoS2 because of the absence of interlayer coupling in former. Nevertheless, the peak positions of A and B excitons are almost the same, even when the layer number changes. This is because of the canceling out of differences between quasi-particle band gap and excitonic binding energy. Furthermore, the threshold energies of the eight CPs are calculated; using these values, the valence and conduction band alignments of the CPs are determined. It is noteworthy that the electronic band structures of MoS2 become stable when the layer number is more than four, which can be attributed to the largely weakened quantum confinement effect in these cases. The results of our study help us better understand the effect of quantum confinement on photoelectronic and photovoltaic applications using MoS2 films.

更新日期：2020-07-01

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南

全部期刊列表>>