采用常压射频等离子体增强化学气相沉积法(AP-PECVD)制备了TiO2纳米晶颗粒薄膜,研究了不同等离子体滞留时间下气相反应对沉积过程的影响,采用发射光谱(OES)测量拟合了等离子体的电子温度Te约为32 492.6 K、离子温度Ti约为850 K,采用热电偶(TC)在线测量等离子体外电极温度T约为662 K;由于沉积所获样品为TiO2锐铁矿晶型,认为等离子体气相温度为662～850 K,主要受功率密度的影响.外加电压和电流的研究结果表明,放电形式为等离子体容性耦合辉光放电.采用场发射扫描电子显微镜(FESEM)、高分辨透射电子显微镜(HRTEM)、X射线衍射(XRD)、拉曼(Raman)等测量了沉积薄膜的形貌和结构,分析后发现:当反应气体在等离子体相滞留时间仅为27 ns时,沉积的薄膜就开始出现明显的锐钛矿相TiO2结晶结构,并均为粒径10 nm左右的纳米颗粒组成的薄膜;同时随着滞留时间的增加,结晶度增加,薄膜的形貌由分离的纳米团簇变为由锐钛矿纳米颗粒连接的多孔均匀薄膜.研究结果对快速制备多孔锐钛矿TiO2纳米晶颗粒薄膜有重要的指导意义.%TiO2 nanocrystalline thin films were prepared by radio frequency atmospheric pressure plasma enhanced chemical vapor deposition (AP-PECVD).The effect of gas phase reaction on the deposition process under different residence time in plasma discharge zone was studied.The plasma electron temperature is about 32492.6 K and ion temperature is about 850 K according to the analysis of the optical emission spectrum(OES).The plasma external electrode temperature is about 662 K measured through thermoelectric couple (TC) and determined mainly by power density.The deposition temperature is therefore estimated to be 662-850 K considering that pure anatase TiO2 product film should be formed below 850 K.The glow discharge mode is verified by discharge current and voltage study results.The morphology and structure of the deposited films were measured by field emission scanning electron microscopy (FESEM),high resolution transmission electron microscopy (HRTEM),X-ray diffraction (XRD) and Raman.The analysis shows that anatase TiO2 nanocrystalline thin films composed of about 10 nm nanoparticles is formed when the residence time of reactive gas in the plasma region is only 27 ns.As the increase of the gas residence time in plasma region,the crystallinity of the film increases.At the same time,the film morphology changes from separated nanoparticulate clusters into porous uniform film closely connected by anatase nanoparticles.This result is practically significant for fast preparation of porous anatase TiO2 nanocrystalline thin films.
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