Tailoring the electronic structure and optical properties of cadmium-doped zinc oxides nanosheet

Abstract

Cd-doped ZnO nanosheet (ZnO NS) were investigated using a full-potential linearized augmented plane wave method within the generalized gradient approximation (GGA) to calculate the electronic structure and its optical response. The calculated band structures have shown that the Cd-doped ZnO NS is a direct band gap semiconductor at Γ with 1.50 eV band gap. The contribution of each atom/orbital were commented in light of total and partial densities of states. We also derived the optical constants (mainly the dielectric constants ε₁(0) and ε₂(0)), the absorption coefficient I(ω), refractive index n(ω), extinction coefficient k(ω), and energy-loss function L(ω). The spectrum of absorption coefficient has revealed to increase rapidly for photon energies higher than 2.5 eV. The absorption spectrum was found to be limited in energy region due to different contributions electronic transitions that occurred within ZnO NS and effect of Cd doping. Reducing the band gap of ZnO NS to low values is suitable process for light-emitting devices and solar cells applications.

Keywords:

• ZnO nanosheet
• solar cells
• DFT
• optical properties
• electronic structure

Public Interest Statement

Graphene and 2D materials in general, have revolutionized our way to perform research and innovate for the benefit of industry and society. They have shown advantageous properties such as flexibility and lightweight. In the future, 2D materials will enable particular innovation of new electronic circuits, due to their exceptional conductive properties. ZnO in 2D or ZnO nanosheet has shown the possibility to tune its electronic and optical properties by an appropriate doping with transition metal. The huge band gap of the ZnO was reduced. In general, 2D materials have shown the ability to tune their physical properties by doping or creation of vacancies.

Additional information

Notes on contributors

Souraya Goumri-Said

This work was achieved by the computational material science group (S. Goumri-Said and M. B. Kanoun) of Physics Department at Alfaisal University (Saudi Arabia) and the researchers from Lahore University (S. Azam) and the University of West Bohemia (S. A. Khan). All researchers have collaborated since 2015 and published joint works using the recent computational theories (density functional theory and the recent approaches of the exchange and correlation term). The present authors have studied different materials such as: chalcogenides and selenides for various applications: magnetism/spintronics, optoelectronic, thermo-electric, and photovoltaic. Recently, the team has extended their interest to new forms of materials: the layered, thin-films, and 2D systems.