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采用脉冲激光沉积(PLD)的方法在玻璃衬底上制备了二氧化钛薄膜,研究了基片温度和氧压对薄膜表面形貌、晶体结构和光学性能的影响。结果表明:当基片温度低于300℃或高于400℃时,二氧化钛薄膜的折射率都随着基片温度的升高而增大;基片温度处于300℃～400℃之间时,折射率随着基片温度的升高而降低;基片温度为300℃时,折射率最大。薄膜的折射率随着氧压的增大而减小。X射线衍射仪(XRD)显示薄膜在基片温度低于300℃时为非晶态结构,在300℃时出现了锐钛矿结构,当基片温度升高到500℃时,薄膜仍为锐钛矿结构;300℃时,薄膜的A(101)衍射峰最强,结晶度最好。通过原子力显微镜(AFM)图分析得出:低于300℃时,随着基片温度的升高,二氧化钛薄膜的晶粒尺寸增大,聚集密度增大;高于300℃时,晶粒的平均尺寸大小几乎不变,300℃时,晶粒排列最均匀有序。根据薄膜的透射谱计算了薄膜的光学带隙,可知随着基片温度的升高,二氧化钛薄膜的带隙变窄;随着氧压的增大,带隙变宽。
Titanium dioxide films were prepared on glass substrates by pulsed laser deposition (PLD). The effects of substrate temperature and oxygen pressure on the surface morphology, crystal structure and optical properties of the films were investigated. The results show that when the substrate temperature is below 300 ℃ or higher than 400 ℃, the refractive index of the TiO2 film increases with the increase of the substrate temperature. When the substrate temperature is between 300 ℃ and 400 ℃, the refractive index The rate decreases as the temperature of the substrate increases; the refractive index is the highest at a substrate temperature of 300 ° C. The refractive index of the film decreases as the oxygen pressure increases. X-ray diffraction (XRD) showed that the film was amorphous when the substrate temperature was below 300 ℃ and anatase structure at 300 ℃. When the substrate temperature was raised to 500 ℃, the film was still sharp Ti (superscript 3 +) shows the highest A (101) diffraction peak and the best crystallinity at 300 ℃. The results of atomic force microscopy (AFM) showed that when the temperature was below 300 ℃, the grain size of titania films increased and the aggregation density increased with the increase of substrate temperature. When the temperature was above 300 ℃, the average grain size Size is almost unchanged, 300 ℃, the most uniform order of grain arrangement. The optical bandgap of the film is calculated from the transmission spectrum of the film. It is found that the bandgap of the titania film becomes narrower as the temperature of the substrate increases. As the oxygen pressure increases, the bandgap becomes wider.