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Anatase TiO2 films are grown on Si (100) by atomic layer deposition. Three different interlayers (Si3N4, Al2O3, and Ti-rich SiOx) between the TiO2 films and the Si substrate have been considered. The band alignment of the titanium oxide films with the silicon substrate is investigated by x-ray photoelectron spectroscopy (XPS), internal photoemission (IPE) spectroscopy, and optical absorption (OA) measurements. XPS analysis indicates that TiO2∕Si heterojunctions with different interlayers (ILs) have different valence-band offsets (VBOs). A VBO value of 2.56±0.09eV is obtained for the TiO2∕Ti-rich SiOx∕Si sample. Similarly, we obtain a VBO value of 2.44±0.09 and 2.73±0.10eV for the TiO2∕Si3N4∕Si and TiO2∕Al2O3∕Si samples, respectively. According to IPE and OA measurements, the band gap of the as-grown TiO2 films is 3.3±0.1eV for all the samples. Combining the XPS and IPE data, the conduction …
Publication date: 
15 Feb 2008

M Perego, G Seguini, G Scarel, M Fanciulli, F Wallrapp

Biblio References: 
Volume: 103 Issue: 4 Pages: 043509
Journal of Applied Physics