The purpose of this paper is to investigate the structural, electronic and optical properties of pure zinc oxide (ZnO) and transition metal (Tm)-doped ZnO using Tm elements from silver (Ag) and copper (Cu) by a first-principles study based on density functional theory (DFT) as implemented in the pseudo-potential plane wave in CASTEP computer code.
The calculations based on the generalized gradient approximation for Perdew-Burke-Ernzerhof for solids with Hubbard U (GGA-PBEsol+U) were performed by applying Hubbard corrections Ud = 5 eV for Zn 3d state, Up = 9 eV for O 2p state, Ud = 6 eV for Ag 4d state and Ud = 9.5 eV for Cu 3d state. The crystal structure used in this calculation was hexagonal wurtzite ZnO with a space group of P63mc and supercell 2 × 2 × 2.
The total energy was calculated to determine the best position for Ag and Cu dopants. The band structures and density of states show that Tm-doped ZnO has a lower bandgaps value than pure ZnO because of impurity energy levels from Ag 4d and Cu 3d states. In addition, Ag-doped ZnO exhibits a remarkable enhancement in visible light absorption over pure ZnO and Cu-doped ZnO because of its lower energy region and extended wavelength spectrum.
The results of this paper are important for the basic understanding of the 3d and 4d Tm doping effect ZnO and have a wide range of applications in designing high-efficiency energy harvesting solar cells.
The authors would like to acknowledge the Ministry of Higher Education Malaysia for funding this research under the KEPU grant 600-RMC/KEPU 5/3 (008/2021) and Universiti Teknologi Mara (UiTM), Cawangan Selangor, Dengkil, Selangor, Malaysia, and Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, Selangor, Malaysia, for providing the facilities and support on this research.
Hamzah, N., Samat, M.H., Johari, N.A., Faizal, A.F.A., Hassan, O.H., Ali, A.M.M., Zakaria, R., Hussin, N.H., Yahya, M.Z.A. and Taib, M.F.M. (2023), "A DFT+U study of structural, electronic and optical properties of Ag- and Cu-doped ZnO", Microelectronics International, Vol. 40 No. 1, pp. 53-62. https://doi.org/10.1108/MI-05-2022-0088
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