Optical and electric properties of Nb-doped anatase TiO2 single crystal

Nb-doped anatase TiO2 single crystal has been grown by chemical vapour transport method. Raman spectra shows that the obtained crystal with Nb of 0.08 wt% has typical anatase structure. An absorption band was observed at around 2.2 eV, which seems to be due to the d-d transition in the conduction band. The electron paramagnetic resonance and electric resistivity measurements show that the doped niobium makes quite shallow donor level whose orbital is d(xy)-like centered at the titanium position of anatase. (C) 2004 Elsevier Ltd. All rights reserved.