We employ x-ray photoelectron spectroscopy (XPS), reflection high-energy electron diffraction (RHEED) and nuclear reaction analysis (NRA) to characterize the concentration-dependent structural properties of nitrogen doping into rutile TiO2. High quality N-doped TiO2 were prepared on rutile single crystal TiO2(110) substrates using plasma-assisted molecular beam epitaxy with an electron cyclotron resonance (ECR) plasma and Ti effusive sources. Films with N dopant concentrations at or below 2 at.% exhibited predominately substitutional doping based on NRA data, whereas films with concentrations above this limit resulted in little or no substitutional N and surfaces rich in Ti3+. The binding energy of the N 1s feature in XPS did not readily distinguish between these two extremes in N-doping, rendering features within 0.4 eV of each other and similar peak profiles. Although widely used to characterize the state of N in anion-doped TiO2 materials, we find that XPS is unsuitable for this task.
Revised: February 28, 2011 |
Published: December 31, 2010
Citation
Henderson M.A., V. Shutthanandan, T. Ohsawa, and S.A. Chambers. 2010.Structural Environment of Nitrogen in N-doped Rutile TiO2(110). In Solar Hydrogen and Nanotechnology V, Proceedings of SPIE, edited by H Idress and H Wang, 7770. Bellingham, Washington:SPIE.PNNL-SA-73720.doi:10.1117/12.862297