Hydrogenated ψ-graphene: Band gap engineering and optical properties
Abstract
Hydrogen passivation was predicted to be an effective method to open the band gap of ψ-graphene by the density functional theory calculations. A critical H coverage of ~60% was found, above which the hydrogenated ψ-graphene opens a band gap. The band gap can be tailored within a wide range of 0-3.57 eV by changing the H coverage. Meanwhile, the opened band gap brings the hydrogenated ψ-graphene different optical properties from the pristine ψ-graphene. Generally, the ψ-graphene possesses the major absorption peaks similar to graphene, except for the redshift of sub-π peak features caused by the pentagons and heptagons. However, hydrogen passivation can result in quite different optical properties from the pristine ψ-graphene for both the absorption peaks and delay. As the H coverage decreases, the absorption coefficient of the hydrogenated ψ-graphene drops independently on the light polarization. Particularly, the absorption delay will be improved during removing the H atoms due to lowering of band gap, which is useful for selective optical absorption.
- Publication:
-
Physica E Low-Dimensional Systems and Nanostructures
- Pub Date:
- January 2020
- DOI:
- 10.1016/j.physe.2019.113701
- Bibcode:
- 2020PhyE..11513701H
- Keywords:
-
- ψ-graphene;
- Hydrogen passivation;
- Band gap engineering;
- Optical property