Polarity modulation in compositionally tunable Bi₂O₂Se thin films

Two-dimensional (2D) materials have emerged as one of most promising candidates to meet the demands of beyond-silicon technology. Among 2D semiconductors, Bi₂O₂Se (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 Zn²⁺ 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 ~10⁶ 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.