Hydrogenated ψ-graphene: Band gap engineering and optical properties

Publication date: Available online 3 September 2019Source: Physica E: Low-dimensional Systems and NanostructuresAuthor(s): Xiaoming Huang, Mengyao Ma, Li Cheng, Lizhao LiuAbstractHydrogen 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.Graphical abstractHydrogen passivation is an effective way to tailor the electronic and optical properties ψ-graphene.

Source: Physica E: Low dimensional Systems and Nanostructures - September 20, 2019 Category: Nanotechnology Source Type: research