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Si:WO3heterostructure for Z-scheme water splitting: an ab initio study
- Source :
- J. Mater. Chem. A. 1:1078-1085
- Publication Year :
- 2013
- Publisher :
- Royal Society of Chemistry (RSC), 2013.
-
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.
Details
- ISSN :
- 20507496 and 20507488
- Volume :
- 1
- Database :
- OpenAIRE
- Journal :
- J. Mater. Chem. A
- Accession number :
- edsair.doi...........b2e89707adf20c9eabd8d44ba610fc35