Lennard-Jones Centre for Computational Materials Science

Effect of trivalent dopants on local coordination and electronic structure in crystalline and amorphous ZnO

Muñoz Ramo, D and Chroneos, A and Rushton, MJD and Bristowe, PD (2014) Effect of trivalent dopants on local coordination and electronic structure in crystalline and amorphous ZnO. Thin Solid Films, 555. pp. 117-121. ISSN 0040-6090

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Abstract

Density functional theory calculations are used to investigate the structure and binding energies of clusters formed between oxygen vacancies and trivalent dopant atoms (indium, gallium and aluminium) substituted into zinc oxide. Our results show that indium atoms form stable nearest neighbour pairs with oxygen vacancies, while gallium and aluminium atoms associate with them at next nearest neighbour sites. Using a combination of classical molecular dynamics and reverse Monte Carlo methods, models of amorphous indium zinc oxide at different compositions up to 25 at.% indium are created. Analysis of these models indicates that, in contrast with the trend observed in the crystal phase, indium does not tend to be undercoordinated in the amorphous phase. The value of the band gap obtained for the amorphous compositions is smaller than that of crystalline undoped ZnO by about 0.8 eV and is largely independent of the indium concentration. Electron-effective masses calculated in all the amorphous models decrease with increasing amount of indium due to the larger dispersion of the In-dominated conduction bands. This trend is compared to resistivity measurements on amorphous indium zinc oxide, which also decrease with increasing indium concentration. © 2013 Elsevier B.V.

Item Type: Article
Uncontrolled Keywords: Amorphous ZnO Defect states DFT In:ZnO Molecular dynamics Pair distribution function Reverse Monte Carlo ZnO
Subjects: UNSPECIFIED
Divisions: UNSPECIFIED
Depositing User: Unnamed user with email sms67@eng.cam.ac.uk
Date Deposited: 08 Mar 2014 08:45
Last Modified: 10 Dec 2020 10:19
DOI: 10.1016/j.tsf.2013.05.140

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