Preparation of functional metal oxide films from aqueous mist using atmospheric pressure glow plasma

为了建立一种新的薄膜制备体系，研究了用常压辉光（APG）等离子体从Zn^<2+>水雾制备ZnO薄膜的方法。等离子体反应器采用管状石英玻璃，铜带双螺旋电极。用振荡器制备Zn^<2+>的水雾，经炉内加热至300ºC，冷凝器冷却至0ºC以下，然后在氩气流中进入反应器，应用60-80W的射频功率制备APG等离子体。在反应器中通过氩气溅射形成细小的ZnO颗粒，并在氩气流中加热到100-200℃的表面。在不同衬底温度下，在玻璃衬底上获得的所有ZnO薄膜的x射线衍射图均显示出具有纤锌矿结构的首选c轴取向。在制备c轴取向ZnO薄膜时，使用氩气和彻底去除水蒸气是非常重要的。通过对该方法制备的ZnO薄膜的形貌与雾的简单热解制备的ZnO薄膜的形貌进行了详细的比较，发现等离子体对薄膜形成过程的影响是溅射效应，从而产生超细颗粒和/或团簇。这一结果延续到后续的常压溅射方法中，采用了类似的管式等离子体反应器。在管式反应器内壁涂覆氧化锌。在反应器中引入氩气，应用60-80W的射频功率制备APG等离子体。在100-400℃的不同温度下，在玻璃衬底上制备的ZnO薄膜的x射线衍射图显示出具有纤锌矿结构的首选C轴取向。

In order to establish a new film preparation system, a search was made for a preparation of ZnO films from Zn^<2+> aqueous mist using atmospheric pressure glow (APG) plasma. The plasma reactor was a pipe type quartz glass with double helical electrodes of copper ribbons. Aqueous mist of Zn^<2+> made by oscillator was passed through the furnace heated at 300ﾟC,condenser cooled to under 0ﾟC and then the reactor in a stream of argon followed by an application of RF power of 60-80W to make APG plasma. Tne fine particles of ZnO formed in the reactor by argon sputtering were brought onto the surface of the substrate heated at 100-200ﾟC in a stream of argon. X-ray diffraction patterns of all ZnO films obtained on glass substrate at various substrate temperature, indicated preferred c-axis orientation with wurtzite structure. It is very important for making c-axis oriented ZnO films that argon gas should be used and the removal of water vapor should be carried out exhaustively. A detailed comparison of the morphologies of ZnO films obtained by this method with that by simple pyrolysis of mist revealed the plasma effect on the film formation process to be sputtering effect to give hyper fine particles and/or clusters. This result was carried over to the following atmospheric pressure sputtering method using similar pipe type plasma reactor. Zinc oxide was coated on inner wall of this pipe type reactor. Argon gas was introduced into the reactor followed by an application of RF power of 60-80W to make APG plasma. X-ray diffraction patterns of all ZnO films obtained on glass substrate at various substrate temperature of 100-400ﾟC indicated preferred c-axis orientation with wurtzite structure.