Polarity modulation in compositionally tunable Bi<sub>2</sub>O<sub>2</sub>Se thin films.

Wang, Yong-Jyun; Zhang, Jian-Wei; Chen, Jianchu; Wang, Haonan; Wu, Shiuan; Lo, Chang-Yu; Hong, Jhe-Ting; Syu, Cheng-Yang et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

Two-dimensional (2D) materials have emerged as one of most promising candidates to meet the demands of beyond-silicon technology. Among 2D semiconductors, Bi<sub>2</sub>O<sub>2</sub>Se (BOSe) stands out as a channel material for advanced electronic applications, due to its high electron mobility and the formation of a native high-k dielectric layer. However, the fabrication of p-type 2D BOSe transistors remains challenging. Here, we report an area-selective doping method at low temperatures (~600 K, compatible with back-end-of-line processes) of pulsed laser deposited BOSe thin films, enabling the modulation of their carrier polarity via the introduction of Zn<sup>2+</sup> substitutional dopants. Taking advantage of this doping strategy, we demonstrate the fabrication of a 2D vertical p-n homojunction with an on/off ratio in photoresponse of ~10<sup>6</sup> and planar transistors based on p-doped BOSe homojunctions. Our results help promoting the application of this material system towards the development of the next-generation electronics.