We have used x-ray photoelectron spectroscopy with high energy resolution to determine band discontinuities at the two buried interfaces of the epitaxial TiO2 (anatase)/ SrTiO3/Si(001) system. The valence band offsets are -2.1 +/- 0.1 eV and +0.2 +/- 0.1 eV at the SrTiO3/Si and TiO2/SrTiO3 heterojunctions, respectively. Assuming bulk band gaps for the SrTiO3 and TiO2 epitaxial films, the associated conduction band offsets are +0.1 +/- 0.1 eV and +0.1 +/- 0.1 eV. Si at the interface is in a flat-band state, indicating a very low density of electronic states. These results suggest that spin polarized electron injection from ferromagnetic Co-doped TiO2 anatase into Si should be facile. PACS numbers: 79.60.Jv, 72.25.Dc
Revised: August 18, 2014 |
Published: November 3, 2003
Citation
Tuan A.C., T.C. Kaspar, T.C. Droubay, J.W. Rogers, and S.A. Chambers. 2003.Band Offsets for the Epitaxial TiO2/SrTiO3/Si(001) System.Applied Physics Letters 83, no. 18:3734-3736.PNNL-SA-39168.