Pore Viljami, Kivelä Tiina, Ritala Mikko, Leskelä Markku
Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014, Helsinki, Finland.
Dalton Trans. 2008 Dec 7(45):6467-74. doi: 10.1039/b809953g. Epub 2008 Oct 9.
Titanium dioxide (TiO2) thin films were grown by atomic layer deposition (ALD) at 300-500 degrees C using TiF4 and H2O as precursors. The films were characterized by FESEM, EDX, UV/Vis and XRD techniques. Two glass types, soda lime and borosilicate, were used as the substrate materials. It was found that the type of the glass substrate had a very strong influence on the growth and properties of the resulting films. At substrate temperatures of 400 and 500 degrees C, the growth rates on borosilicate were 0.8 and 1.0 A per cycle, respectively, and the films were mainly anatase. With the same deposition conditions on soda lime, rutile phase was formed and the growth rates were 1.1 and 1.5 A per cycle, respectively. Growth saturation was confirmed for both glass substrates at 400 degrees C by varying the pulse lengths of the precursors. Both anatase and rutile films prepared at 400-500 degrees C possessed photocatalytic activity in degrading stearic acid under UV and visible light, whereas the films prepared at 300 degrees C had virtually no activity. All the films, including those prepared at 300 degrees C, turned superhydrophilic under UV light.
采用四氟化钛（TiF₄）和水作为前驱体，通过原子层沉积（ALD）在300 - 500摄氏度的温度下生长二氧化钛（TiO₂）薄膜。使用场发射扫描电子显微镜（FESEM）、能量散射X射线光谱仪（EDX）、紫外可见光谱仪（UV/Vis）和X射线衍射仪（XRD）技术对薄膜进行表征。使用两种玻璃类型，即钠钙玻璃和硼硅酸盐玻璃作为衬底材料。发现玻璃衬底的类型对所得薄膜的生长和性能有非常强烈的影响。在400和500摄氏度的衬底温度下，硼硅酸盐玻璃上的生长速率分别为每循环0.8和1.0埃，并且薄膜主要为锐钛矿型。在相同的沉积条件下，钠钙玻璃上形成了金红石相，生长速率分别为每循环1.1和1.5埃。通过改变前驱体的脉冲长度，证实了两种玻璃衬底在400摄氏度时都达到了生长饱和。在400 - 500摄氏度制备的锐钛矿型和金红石型薄膜在紫外光和可见光下都具有降解硬脂酸的光催化活性，而在300摄氏度制备的薄膜几乎没有活性。所有薄膜，包括在300摄氏度制备的薄膜，在紫外光下都变成超亲水的。
