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Issue 4, 2013
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Si:WO3 heterostructure for Z-scheme water splitting: an ab initio study

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Abstract

The Si:WO3 heterostructure is expected to have suitable band alignment for the Z-scheme water splitting, but the heterostructure interfaces have been scarcely studied. In this work, a series of interfaces between the WO3 (100) and Si (001) surfaces, which have a small lattice-mismatch, are studied using ab initio calculations. When there is no atom diffusion across the interface, a Si–O bonded interface with Si dimers is the most stable. Analysis of the electronic structure shows that the interfacial Si and O atoms are fully saturated, leading to a clean interface without localized gap states. O diffusion from WO3 into Si is found to be thermodynamically possible, but it does not affect the full bond saturation of the interfacial atoms. A type-II band alignment exists between Si and WO3, with the WO3 conduction band about 0.5 eV higher than the Si valence band, which is not influenced by O diffusion. A band diagram is plotted for the Si:WO3 heterostructure to evaluate its photocatalytic capability, and the influence of the small Schottky barrier and the interface amorphous layer is discussed.

Graphical abstract: Si:WO3 heterostructure for Z-scheme water splitting: an ab initio study

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Publication details

The article was received on 25 Sep 2012, accepted on 06 Nov 2012 and first published on 08 Nov 2012


Article type: Paper
DOI: 10.1039/C2TA00441K
Citation: J. Mater. Chem. A, 2013,1, 1078-1085
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    Si:WO3 heterostructure for Z-scheme water splitting: an ab initio study

    W. Wang, S. Chen, P. Yang, C. Duan and L. Wang, J. Mater. Chem. A, 2013, 1, 1078
    DOI: 10.1039/C2TA00441K

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