Abstract Reduced titania phases such as Ti2O3, Ti3O5, and TixO2x-1 (the magneli phase, 4 ≤ x ≤10) are collectively a promising class of materials due to the stoichiometric tunability of their electronic structure in stoichiometric compositions. This flexibility, combined with their relatively high electrical conductivity, high corrosion resistance, and photostability makes reduced titania a candidate for many applications. In this work, stable reduced titania films were synthesized on silicon substrates via pulsed laser deposition (PLD) under a forming gas environment at elevated temperatures. The atomic/electronic structure and the electrical properties of the PLD reduced titania films were investigated using four-point probe, Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy (XAS), and ultraviolet photoelectron spectroscopy (UPS). The PLD films demonstrated a notable decrease in resistivity compared to those of stoichiometric TiO2 films reported in literature. Raman and XAS revealed that the observed resistivities in these films are correlated to substoichiometric titania phases (Ti2O3 between 400-600 °C and the Ti3O5-like at 700 °C) present in them. UPS measurements on the sub-stoichiometric titania indicated a decrease in the work functions with a decrease in the titanium oxidation state. The ability to tune such electrical properties with careful control of preparation is key to improved performance.

中文翻译：

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二氧化钛电子特性的亚化学计量调整

摘要 还原的二氧化钛相如 Ti2O3、Ti3O5 和 TixO2x-1（magneli 相，4 ≤ x ≤ 10）是一类很有前途的材料，因为它们的电子结构在化学计量组成中具有化学计量可调性。这种灵活性与其相对较高的导电性、高耐腐蚀性和光稳定性相结合，使还原二氧化钛成为许多应用的候选者。在这项工作中，在高温合成气体环境下，通过脉冲激光沉积 (PLD) 在硅衬底上合成了稳定的还原二氧化钛薄膜。使用四点探针，拉曼光谱，X射线光电子能谱，X射线吸收光谱（XAS）研究了PLD还原二氧化钛薄膜的原子/电子结构和电性能，和紫外光电子能谱（UPS）。与文献中报道的化学计量 TiO2 薄膜相比，PLD 薄膜的电阻率显着降低。拉曼和 XAS 表明，在这些薄膜中观察到的电阻率与它们中存在的亚化学计量二氧化钛相（400-600°C 之间的 Ti2O3 和 700°C 的类 Ti3O5）相关。UPS 对亚化学计量二氧化钛的测量表明，随着钛氧化态的降低，功函数降低。通过仔细控制制备来调整此类电学特性的能力是提高性能的关键。拉曼和 XAS 表明，在这些薄膜中观察到的电阻率与它们中存在的亚化学计量二氧化钛相（400-600°C 之间的 Ti2O3 和 700°C 的类 Ti3O5）相关。UPS 对亚化学计量二氧化钛的测量表明，随着钛氧化态的降低，功函数降低。通过仔细控制制备来调整此类电学特性的能力是提高性能的关键。拉曼和 XAS 表明，在这些薄膜中观察到的电阻率与它们中存在的亚化学计量二氧化钛相（400-600°C 之间的 Ti2O3 和 700°C 的类 Ti3O5）相关。UPS 对亚化学计量二氧化钛的测量表明，随着钛氧化态的降低，功函数降低。通过仔细控制制备来调整此类电学特性的能力是提高性能的关键。