Influence of Annealing Temperature on the Properties of Sol-Gel Deposited Nb-Doped TiO_2 Thin Films

摘要

Nb-doped TiO_2 (TNO) thin films were prepared by a sol-gel spin coating method with Nb content of 5 at.%, and then annealed in the temperature range of 500-900 oC. The surface morphologies and the crystalline phases of the TNO thin films were investigated by using SEM and XRD patterns. The grain sizes increased with rising annealing temperature, and the crystalline phases were completely transformed from anatase into rutile when the annealing temperature was above 900 oC in air atmosphere. In addition, the optical band gap decreased and the average optical transmittance was between 75 and 70 % in the range of visible light. Furthermore, the better electrical properties were obtained at the annealing temperature of 600 oC.