Effect of TiO<sub>2</sub> Film Thickness on the Stability of Au<sub>9</sub> Clusters with a CrO<sub>x</sub> Layer

oleh: Abdulrahman S. Alotabi, Yanting Yin, Ahmad Redaa, Siriluck Tesana, Gregory F. Metha, Gunther G. Andersson

Format: Article
Diterbitkan: MDPI AG 2022-09-01

Deskripsi

Radio frequency (RF) magnetron sputtering allows the fabrication of TiO<sub>2</sub> films with high purity, reliable control of film thickness, and uniform morphology. In the present study, the change in surface roughness upon heating two different thicknesses of RF sputter-deposited TiO<sub>2</sub> films was investigated. As a measure of the process of the change in surface morphology, chemically -synthesised phosphine-protected Au<sub>9</sub> clusters covered by a photodeposited CrO<sub>x</sub> layer were used as a probe. Subsequent to the deposition of the Au<sub>9</sub> clusters and the CrO<sub>x</sub> layer, samples were heated to 200 ℃ to remove the triphenylphosphine ligands from the Au<sub>9</sub> cluster. After heating, the thick TiO<sub>2</sub> film was found to be mobile, in contrast to the thin TiO<sub>2</sub> film. The influence of the mobility of the TiO<sub>2</sub> films on the Au<sub>9</sub> clusters was investigated with X-ray photoelectron spectroscopy. It was found that the high mobility of the thick TiO<sub>2</sub> film after heating leads to a significant agglomeration of the Au<sub>9</sub> clusters, even when protected by the CrO<sub>x</sub> layer. The thin TiO<sub>2</sub> film has a much lower mobility when being heated, resulting in only minor agglomeration of the Au<sub>9</sub> clusters covered with the CrO<sub>x</sub> layer.