Abstract Nanocomposite based on Palladium (Pd) Coated TiO2/Si nanopillars is an attractive candidate for photocatalytic applications because of its outstanding electrochemical and optical characteristics. In this research, Pd/TiO2/Si nanopillars were synthesized by combination of metal-assisted chemical etching and atomic layer deposition, and then the surface was investigated by means of Electron microscopy, Time-of-Flight Secondary Ion Mass-Spectrometry (ToF-SIMS), Auger Electron Spectroscopy (AES) and X-Ray Photoelectron spectroscopy (XPS). The spatial distribution of different chemical components and contaminations on the surface of the produced nanocomposites was evaluated by ToF-SIMS mapping. Depth profiling by AES was carried out to determine the chemical composition and the conformality of Pd and TiO2 layer over the Si pillars. The elemental composition and stoichiometry were determined by XPS analysis. The XPS valence band analysis was performed in order to investigate the modification of TiO2/Si nanopillars electronic structure after Pd deposition. It was found that the Pd coating decreases the concentration of photoactive defects that can reduce the photoelectrochemical efficiency of TiO2.

中文翻译：

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钯涂层 TiO2/Si 纳米柱的原子层沉积：ToF-SIMS、AES 和 XPS 表征研究

摘要 基于钯 (Pd) 包覆的 TiO2/Si 纳米柱的纳米复合材料因其出色的电化学和光学特性而成为光催化应用的有吸引力的候选材料。本研究采用金属辅助化学蚀刻和原子层沉积相结合的方法合成了 Pd/TiO2/Si 纳米柱，然后通过电子显微镜、飞行时间二次离子质谱 (ToF- SIMS)、俄歇电子能谱 (AES) 和 X 射线光电子能谱 (XPS)。通过 ToF-SIMS 映射评估了所生产的纳米复合材料表面上不同化学成分和污染物的空间分布。通过 AES 进行深度分析，以确定 Si 柱上 Pd 和 TiO2 层的化学成分和共形性。通过XPS分析确定元素组成和化学计量。进行 XPS 价带分析是为了研究 Pd 沉积后 TiO2/Si 纳米柱电子结构的改性。发现 Pd 涂层降低了光活性缺陷的浓度，从而降低了 TiO2 的光电化学效率。