Issue 35, 2020

Transition from an indirect type-I to a direct type-II bandgap in α-tellurene/Ca(OH)2 heterostructures with excellent optical properties

Abstract

Exploring van der Waals heterostructures (vdWHs) based on two-dimensional (2D) materials is of importance for designing new materials or tuning the properties of existing materials. By virtue of first-principles calculations, we propose a type-I vertical 2D α-tellurene/Ca(OH)2 vdWH with an indirect bandgap of 1.10 eV, in which both the CBM and VBM originate completely from tellurene. In addition, we also show that such a vdWH presents excellent optical absorption and an unexpectedly hyperbolic nature, which is mainly determined by tellurene. Hyperbolic materials play a central role in nanophotonics. In tellurene and Te-based materials, we for the first time report this natural hyperbolic property, which was previously unknown. More importantly, under in-plane biaxial strain or vertical strain, the α-tellurene/Ca(OH)2 bilayer transforms into a direct bandgap type-II vdWH, in which both the CBM and VBM located at the Γ point are contributed by the tellurene and Ca(OH)2 monolayers, respectively. Meanwhile, the application of strain can also be used to tune the optical absorption and the frequency range of the hyperbolic property. Our findings extend the applications of tellurene and Te-based vdWHs in nanodevices and provide some guidance for investigating the related vdWHs.

Graphical abstract: Transition from an indirect type-I to a direct type-II bandgap in α-tellurene/Ca(OH)2 heterostructures with excellent optical properties

Supplementary files

Article information

Article type
Paper
Submitted
09 Jun 2020
Accepted
30 Jul 2020
First published
05 Aug 2020

J. Mater. Chem. C, 2020,8, 12291-12301

Transition from an indirect type-I to a direct type-II bandgap in α-tellurene/Ca(OH)2 heterostructures with excellent optical properties

X. Cai, W. Chen, X. Jia, L. Zhang, Q. Wang, B. Wang, X. Yang, Y. Liu and Y. Jia, J. Mater. Chem. C, 2020, 8, 12291 DOI: 10.1039/D0TC02741C

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements