Oxygen vacancies play crucial roles in determining the physical properties of metal oxides, representing important building blocks in many scientific and technological fields due to their unique chemical, physical, and electronic properties. However, oxygen vacancies are often invisible because of their dilute concentrations. Therefore, characterizing and quantifying their presence is of utmost importance for understanding and realizing functional metal oxide devices. This, however, is oftentimes a non-trivial task. In this Perspective paper, we discuss the relevant regimes of concentrations and associated phenomena arising from oxygen vacancies. We then focus on experimental techniques available for observing oxygen vacancies at widely different levels of concentrations. Finally, we discuss current challenges and opportunities for utilizing oxygen vacancies in metal oxides.

中文翻译：

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氧空位：氧化物电子的（无形）朋友

氧空位在决定金属氧化物的物理性质方面起着至关重要的作用，由于其独特的化学、物理和电子性质，它代表了许多科学和技术领域的重要组成部分。然而，氧空位由于其稀浓度而通常是不可见的。因此，表征和量化它们的存在对于理解和实现功能性金属氧化物器件至关重要。然而，这通常是一项重要的任务。在这篇 Perspective 论文中，我们讨论了由氧空位引起的相关浓度和相关现象。然后，我们专注于可用于观察不同浓度水平氧空位的实验技术。最后，