Deep-level optical spectroscopy investigation of N-doped TiO2 films -: art. no. 132104

N-doped TiO2 films were deposited on n(+)-GaN/Al2O3 substrates by reactive magnetron sputtering and subsequently crystallized by annealing at 550 degrees C in flowing N-2 gas. The N-doping concentration was similar to 8.8%, as determined from x-ray photoelectron spectroscopy measurements. Deep-level optical spectroscopy measurements revealed two characteristic deep levels located at similar to 1.18 and similar to 2.48 eV below the conduction band. The 1.18 eV level is probably attributable to the O vacancy state and can be active as an efficient generation-recombination center. Additionally, the 2.48 eV band is newly introduced by the N doping and contributes to band-gap narrowing by mixing with the O 2p valence band. (C) 2005 American Institute of Physics.