Two-dimensional (2D) electron systems are promising for investigating correlated quantum phenomena. In particular, 2D oxides provide a platform that can host various quantum phases such as quantized Hall effect, superconductivity, or magnetism. The realization of such quantum phases in 2D oxides heavily relies on dedicated heterostructure growths. Here we show the integer quantum Hall effect achieved in chemical vapor deposition grown Bi₂O₂Se - a representative member of a more accessible oxide family. A single or few subband 2D electron system can be prepared in thin films of Bi₂O₂Se, where the film thickness acts as the key subband design parameter and the occupation is determined by the electric field effect. This oxide platform exhibits characteristic advantages in structural flexibility due to its layered nature, making it suitable for scalable growth. The unique small mass distinguishes Bi₂O₂Se from other high-mobility oxides, providing a new platform for exploring quantum Hall physics in 2D oxides.

二维 （2D） 电子系统有望研究相关量子现象。特别是，二维氧化物提供了一个可以承载各种量子相位的平台，例如量子霍尔效应、超导性或磁性。在 2D 氧化物中实现这种量子相在很大程度上依赖于专用的异质结构生长。在这里，我们展示了在化学气相沉积生长的 Bi₂O₂Se 中实现的整数量子霍尔效应 - 一种更容易接近的氧化物家族的代表成员。可以在 Bi₂O₂Se 的薄膜中制备单个或几个子带 2D 电子系统，其中膜厚作为关键的子带设计参数，占用由电场效应决定。由于其分层性质，这种氧化物平台在结构灵活性方面表现出特征优势，使其适合可扩展生长。独特的小质量将 Bi₂O₂Se 与其他高迁移率氧化物区分开来，为探索二维氧化物中的量子霍尔物理学提供了新的平台。