Titanium dioxide thin films were deposited by the reactive ion-assisted sputtering method from titanium targets at various partial pressures and deposition parameters. The films were deposited onto substrates at temperatures ranging from room-temperature conditions to 722 K. A selection of thin films was post-deposited annealed at temperatures up to 972 K for 10 min and characterized by micro-Raman spectroscopy and scanning electron microscopy (SEM) and subsequently analysed to assess their photocatalytic activity. Micro-Raman characterization revealed that the as-deposited films had either predominant amorphous, rutile-like structures, anatase-like structures or anatase-rutile mixed structures. The thin films deposited with a high substrate temperature and with energy assistance from the ion source tended to be amorphous, while films deposited on a hot substrate without ion energy assistance tended to have a mixed crystalline phase. On subsequent annealing the amorphous films changed to a rutile structure at temperatures above 672 K, while mixed anatase-rutile films changed to predominant rutile structures only after thermal treatments above 872 K. Thus, this study has revealed an astonishing persistence of the anatase-rutile mixed phase at very high temperatures and showed the possible existence of a key transition temperature at 672 K, where it was possible to see a transformation from amorphous or mixed phase to a rutile or dominant rutile mixed phase. Photocatalytic tests were undertaken by using a novel method consisting of observing the degradation of a film of stearic acid by the thin films under artificial UV radiation. Of the films investigated those with anatase-rutile mixed phases showed the greatest photoactivity. This work was essential in the understanding of the correlation between growth deposition conditions, phase transitions and photocatalytic activity. This set of experiments demonstrated that titania made under a highly oxidizing atmosphere, with no temperature applied on the substrate during fabrication and using an ion sputtering method, is a useful and valuable novel method for creating active TiO₂ thin films.

通过反应离子辅助溅射法在不同的分压和沉积参数下，从钛靶材上沉积二氧化钛薄膜。将薄膜在室温至722 K的温度范围内沉积到基板上。在972 K的最高温度下将一系列薄膜进行后沉积退火10分钟，并通过显微拉曼光谱和扫描电子显微镜（SEM）进行表征），然后进行分析以评估其光催化活性。显微拉曼表征表明，所沉积的膜具有主要的无定形，金红石样结构，锐钛矿样结构或锐钛矿-金红石混合结构。在较高的基板温度和离子源的能量辅助下沉积的薄膜往往是非晶态的，而在没有离子能辅助的情况下沉积在热基板上的薄膜往往具有混合晶相。在随后的退火过程中，非晶态膜在高于672 K的温度下变为金红石结构，而混合的锐钛矿-金红石膜仅在872 K以上的热处理后才变为主要的金红石结构。因此，这项研究显示了锐钛矿-金红石的惊人持久性混合相在非常高的温度下显示出可能存在的关键转变温度为672 K，在那里可以看到从无定形或混合相到金红石或主要金红石混合相的转变。通过使用一种新颖的方法进行光催化测试，该方法包括在人工UV辐射下观察薄膜对硬脂酸膜的降解。在所研究的薄膜中，具有锐钛矿-金红石混合相的薄膜显示出最大的光活性。这项工作对于理解生长沉积条件，相变和光催化活性之间的相关性至关重要。这组实验表明，在高氧化性气氛下制备的二氧化钛是一种有用且有价值的新颖方法，可用于制备活性TiO，该二氧化钛是在制造过程中未在基板上施加温度且使用离子溅射法制备的。₂薄膜。