Bi₂O₂Se: A rising star for semiconductor devices

With weak interlayer interactions and unique physical properties, bismuth oxyselenide (Bi₂O₂Se) has become a rising star as a novel quasi-2D material, possessing high symmetry, adjustable electronic structure, ultra-high electron mobility, persistent quantum oscillations, unique defects, strong spin-orbital coupling, natural oxide layers, excellent stability, and marvelous optoelectronic performance. These characteristics will help to break through existing technical barriers for applications such as field-effect transistors and photodetectors. Its unique crystal structure and suitable lattice parameters allow it to grow on lattice-matched (SrTiO₃ and LaAlO₃) and unmatched (mica and SiO₂) substrates, establishing a link between traditional epitaxy and emerging van der Waals epitaxy. This review aims to provide an overview of this promising semiconductor from a fundamental structure, physics, and physical properties perspective. We especially pay attention to the correlation of electronic structure to various physical properties and material performance. We also identify current problems and challenges regarding the fundamental properties of this material.