光催化TiO_2薄膜的溅射沉积技术

Sputtering deposition technology of photocatalytic TiO_2 films

采用直流反应溅射技术可以制备出具有光催化作用的TiO2薄膜。这种TiO2薄膜经紫外光辐照后,可以分解有机物以及降低水和TiO2薄膜表面之间的接触角。然而,普通的直流反应溅射在制备介质膜时,普遍都存在着工艺不稳定、沉积速率低的问题,所以它不适合于工业化生产。脉冲磁控溅射与直流磁控溅射相比,它在基体表面附近具有较高的等离子体密度以及带电粒子具有较高的能量,这对于TiO2在低温下结晶十分有利。此外,采用双极脉冲模式生长的TiO2薄膜,它的光催化特性要优于单极脉冲模式。这种双极脉冲溅射并结合等离子体发射监控(PEM),使得工艺稳定性得到了改善,沉积速率亦得到了提高。

Photocatalytic TiO_2 films were successfully prepared by DC reactive magnetron sputtering. After UV irradiation, the TiO_2 films can decompose organic substances and reduce the contact angles they make with water droplets. However, during the preparation of dielectric layers, the conventional DC reactive sputtering process has the defects of instability and comparative low deposition rate in general, which make the process often unsuitable in industrial production. Comparing with the DC sputtering method, pulse sputtering technology can provide a higher plasma density and higher energy of charged particles in the vicinity of substrate surface, both are beneficial to the low-temperature crystallization of TiO_2. Furthermore, the anatase phase TiO_2 films growing in bipolar pulse mode show a higher photocatalytic activitiy than those growing in unipolar mode. The bipolar pulse sputtering technology in combination with PEM control circuits will improve the process stability as well as the deposition rate.