Lennard-Jones Centre for Computational Materials Science

Hybrid density functional calculations of the defect properties of ZnO:Rh and ZnO:Ir

Muñoz Ramo, D and Bristowe, PD (2014) Hybrid density functional calculations of the defect properties of ZnO:Rh and ZnO:Ir. Thin Solid Films, 555. pp. 112-116. ISSN 0040-6090

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Abstract

We report density functional calculations of the atomic and electronic structure of the spinel phases ZnRh2O4 and ZnIr 2O4 as well as crystalline ZnO lightly doped (1 at.%) with Rh and Ir ions using the B3LYP hybrid functional. Calculations for the spinels show band gaps (~ 3 eV) and lattice parameters (~ 2% difference) in reasonable agreement with experimental data. Incorporation of the transition metals into ZnO induces local distortions in the lattice and the appearance of metal d levels in the low gap region and near the conduction band minimum, with a d-d splitting of about 2 eV, which reduces the effective transparency of the material. Addition of a hole to the simulation cell of both spinels and doped ZnO leads to charge localization in the neighbourhood of Rh/Ir accompanied by local lattice deformations to form a small polaron which may lead to low hole mobility. We calculate polaron diffusion barriers in the spinels and obtain values around 0.02-0.03 eV. These very low barrier energies suggest that at high Rh/Ir concentrations polaron hopping is not going to be detected at room temperature. © 2013 Elsevier B.V.

Item Type: Article
Uncontrolled Keywords: DFT Diffusion barrier Polaron ZnIr2O4 ZnO ZnRh2O4
Subjects: UNSPECIFIED
Divisions: UNSPECIFIED
Depositing User: Unnamed user with email sms67@eng.cam.ac.uk
Date Deposited: 08 Mar 2014 08:45
Last Modified: 19 Jun 2021 13:44
DOI: 10.1016/j.tsf.2013.08.013

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