退火温度对纳米TiO2薄膜微结构的影响

利用XRD、IR、UV-VIS、AFM、XPS等手段,研究了退火温度对溶胶–凝胶法制备的纳米TiO2薄膜微结构和表面形貌的影响。450~600℃退火处理的薄膜呈锐钛矿和金红石型混晶结构,700℃退火后为纯金红石相;水峰的吸收峰消失在300~500℃之间,至500℃有机基团完全消失,薄膜表面主要有C,Ti,O三种元素;改变退火温度,可以使薄膜的禁带宽度在3.26~3.58eV之间变化,可以在一定范围内,获得不同折射率的TiO2纳米薄膜;薄膜的表面粗糙度(RMS)为2~3nm。

Influence of Annealing Temperature on the Microstructure of TiO2 Nanometer Thin Films

The influence of annealing temperature on the microstructure and surface morphology of TiO2 nanometer thin films prepared by sol-gel method were studied. The microstructure and surface morphology were examined by XRD、IR、 UV-VIS、AFM and XPS. The film was consisted of anatase and rutile phase annealed at 450℃ to 600℃. After being annealed at 700℃, the structure of TiO2 thin film changed into rutile completely. In the film, besides Ti and O elements, there are a certain amount of residual carbon from the starting organometallic components and a small amount of sodium ions diffused from the glass substrates. The refraction index (n) increases from 1.944 to 2.037 as the anneal temperature increasing (350~500 ℃) and the indirect optical absorption band gaps (Eg) decreases from 3.58 eV to 3.26 eV as anneal temperature increasing (350~650℃). AFM result shows that the RMS of films is about 2~3 nm.