Paul Mousri, Karmakar Sabyasachi, Tripathi Shilpa, Jha S N, Satpati Biswarup, Chakraborty Supratic
Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India.
Homi Bhabha National Institute, BARC Training School Complex, Anushaktinagar, Mumbai 400094, India.
J Chem Phys. 2024 May 28;160(20). doi: 10.1063/5.0206709.
The outstanding catalytic property of cerium oxide (CeO2) strongly depends on the polaron formation due to the oxygen vacancy (V̈O) defect and Ce4+ to Ce3+ transformation. Temperature plays an important role in the case of polaron generation in CeO2 and highly influences its electrical transport properties. Therefore, a much needed attention is required for detailed understanding of the effect of temperature on polaron formation and oxygen vacancy migration to get an idea about the improvement in the redox property of ceria. In this work, we have probed the generation of polarons in CeO2 thin-film deposited on a silicon (Si) substrate using the resonance photoemission spectroscopy (RPES) study. The RPES data show an increase in polaron density at the substrate-film interface of the thermally annealed film, indicating the formation of an interfacial Ce2O3 layer, which is, indeed, a phase change from the cubic to hexagonal structure. This leads to a modified electronic band structure, which has an impact on the capacitance-voltage (C-V) characteristics. This result nicely correlates the microscopic property of polarons and the macroscopic transport property of ceria.
氧化铈（CeO₂）出色的催化性能很大程度上取决于因氧空位（V̈O）缺陷和Ce⁴⁺到Ce³⁺转变而形成的极化子。在CeO₂中极化子产生的情况下，温度起着重要作用，并对其电输运性质有很大影响。因此，为了详细了解温度对极化子形成和氧空位迁移的影响，从而了解二氧化铈氧化还原性能的改善情况，需要给予更多关注。在这项工作中，我们使用共振光发射光谱（RPES）研究探测了沉积在硅（Si）衬底上的CeO₂薄膜中极化子的产生。RPES数据显示，热退火薄膜的衬底 - 薄膜界面处极化子密度增加，表明形成了界面Ce₂O₃层，实际上这是从立方结构到六方结构的相变。这导致了电子能带结构的改变，进而对电容 - 电压（C - V）特性产生影响。这一结果很好地关联了极化子的微观性质和二氧化铈的宏观输运性质。
