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

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 dxy-like centered at the titanium position of anatase.