Abstract: Since the discovery of graphene, two-dimensional (2D) materials have been a research hotspot. 2D semiconductor materials, with their atomic-level thickness and excellent electronic and optoelectronic properties, are considered ideal semiconductor materials. However, van der Waals materials account for only 5% of the crystal structure database, resulting in a limited number of 2D materials to be studied, which restricts their development and application. The development of non-van der Waals 2D materials will greatly enrich the family of 2D semiconductor materials. However, the two-dimensional growth of non-van der Waals materials remains a significant challenge, as conventional synthesis methods struggle to limit their growth in three dimensions. This study developed a one-step chemical vapor deposition method to grow non-van der Waals 2D Bi₂WO₆ nanosheets on C-plane sapphire with an average size of 60 μm. Furthermore, the thickness of the 2D Bi₂WO₆ nanosheets was precisely controlled by adjusting the growth parameters. The Bi₂WO₆ nanosheets were used to construct a top-gate FET, achieving an on/off ratio as high as 10⁶ and a carrier mobility of 2.4 cm²∙V^-1∙s^-1. This study also constructed a photodetector that achieved a specific detectivity of up to 3.6 × 10¹⁰, a responsivity of 0.779 A·W^-1, and an EQE of 218.5%. This research demonstrates that 2D Bi₂WO₆ holds promise as an ideal material for future electronic and optoelectronic devices.

Key words: Bi₂WO₆, 2D semiconductor, chemical vapor deposition, field-effect transistors, photodetectors