Probing and modifying the empty-state threshold of anatase TiO2: Experiments and ab initio theory
2008 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 78, no 7, 075113- p.Article in journal (Refereed) Published
O 1s x-ray absorption spectroscopy (XAS) in conjunction with photoelectron spectroscopy has been used to explore the conduction-band edge of single crystalline and nanostructured anatase TiO2. The experiments are supported by ab initio density-functional calculations in which both the initial and core hole final states are considered. The calculations show that the states at the conduction-band edge of anatase are of pure d(xy) character. This is also the case in the presence of an O 1s core hole. In the O 1s XAS process pure Ti d states cannot be probed and, by appropriate energy referencing, the separation between the Ti d derived conduction-band edge and the threshold of the unoccupied Ti d-O p states can therefore be revealed. The electronic charge needed per Ti to eliminate this offset is discussed in quantitative terms. The theoretical and experimental values are in good agreement, showing that 4 +/- 2% of an electronic charge per Ti ion is sufficient to change the character of the empty states at threshold from pure Ti d to Ti d-O p.
Place, publisher, year, edition, pages
2008. Vol. 78, no 7, 075113- p.
Electron density of states and band structure of crystalline solids, Surface states, band structure, electron density of states, Clean metal, semiconductor, and insulator surfaces, X-ray absorption spectra
IdentifiersURN: urn:nbn:se:uu:diva-107890DOI: 10.1103/PhysRevB.78.075113ISI: 000259406700035OAI: oai:DiVA.org:uu-107890DiVA: diva2:233448