Simulation Evidence of Hexagonal‐to‐Tetragonal ZnSe Structure Transition: A Monolayer Material with a Wide‐Range Tunable Direct Bandgap

Advanced Science

Lei Li²  Pengfei Li¹  Ning Lu²  Jun Dai² 

[1] Hefei National Laboratory for Physical Sciences at Microscale and Collaborative Innovation Center of Chemistry for Energy Materials, University of Science and Technology of China, Hefei, Anhui, P.R. China;Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE, USA

关键词: light emitting and absorption;    strain engineering;    tetragonal ZnSe monolayer;    wide‐range tunable direct bandgap;   

DOI  :  10.1002/advs.201500290

来源: Wiley

【 摘 要 】

Abstract

2D material with tunable direct bandgap in the intermediate region (i.e., ≈2–3 eV) is key to the achievement of high efficiency in visible-light optical devices. Herein, a simulation evidence of structure transition of monolayer ZnSe from the experimental pseudohexagonal structure to the tetragonal structure (t-ZnSe) under lateral pressure is shown, suggesting a possible fabrication route to achieve the t-ZnSe monolayer. The as-produced t-ZnSe monolayer exhibits highly tunable bandgap under the biaxial strains, allowing strain engineering of t-ZnSe's bandgap over a wide range of 2–3 eV. Importantly, even under the biaxial strain up to 7%, the t-ZnSe monolayer still keeps its direct-gap property in the desirable range of 2.40–3.17 eV (corresponding to wavelength of green light to ultraviolet). The wide-range tunability of direct bandgap appears to be a unique property of the t-ZnSe monolayer, suggesting its potential application as a light-emitting 2D material in red–green–blue light emission diodes or as complementary light-absorption material in the blue–yellow region for multijunction solar cells. The straddling of the band edge of the t-ZnSe monolayer over the redox potential of water splitting reaction also points to its plausible application for visible-light-driven water splitting.

【 授权许可】

CC BY   
© 2015 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.