Research On Preparation And Properties Of N Doped TiO₂Films

The control and management of environmental pollution is the major problems for the21st century to face and solve. In recently, the research of using photocatalytic oxidation technology to solve the water, air, soil and other environmental pollution problems is developing. As the second generation photocatalytic materials, N doped TiO2(N-TiO2) is the representative photocatalyst, which could be stimulated by the visible range light. With the different N/O atom ratio, the N-TiO2film could show the complicated structure and different properties, such as the optical property, which has the great significance to the application in various fields.In this paper, the direct current (DC) pulsed magnetron sputtering method and ion source auxiliary magnetron sputtering methods were used to prepare the N-TiO2film at room temperature. The ultraviolet-visible spectra, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscope (AFM) were carried out to all samples. By these technigues, the transmittance, reflectance, crystal structure, composition, surface morphology of N-TiO2film were analyzed.The main results were showed as the followings:1. For DC pulsed magnetron sputtering, with the other conditions constant, O2flow rate increased from2to12seem, the N-TiO2films deposition rate reduced monotonously from3.02to0.82. The absorbency of N-TiO2films were about constant. The composition of N-TiO2films were mainly Ti, O, and N. The stoichiometric did not change with the increase of O2flow rate. The N atom ratio is only about4at.%. The diffraction peak relative intensity of anatase (101) increasingly enhanced, which meant the film changed from the amorphous structure to nano crystal structure, gradually. Besides, before and after the annealing treatment, no Ti-N phase was found in the films. After the annealing treatment, the band gap decreased gradually with the increase of O2flow rate.2. For DC pulsed magnetron sputtering, with the other conditions constant, the N2flow increased from2to10seem, the N-TiO2films deposition rate reduced monotonously. The absorbency of N-TiO2films were about constant. The absorbency of films also reduced gradually. The N atom ratio decreased monotonously from4.63to0.78. The density of films surface islands and the root mean square (RMS) roughness increased monotonously.3. For ion source auxiliary magnetron sputtering, with the other conditions constant, the working pressure of ion source increased from0.1to0.9Pa. The absorbency of N-TiO2films increased gradually from4.1%to45.5%. With the increase of ion source working pressure, the N/Ti atom ratio increased monotonously, which the N element could reach at20.11at.%for0.9Pa. The dop depth was about110nm. The density of films surface island structure and the RMS roughness increased monotonously.