Quantum oscillation in epitaxial Bi2O2Se thin film prepared by pulsed laser deposition

Bi2O2Se (BOS), due to its high carrier mobility, strong spin–orbit coupling effect, and air stability, has garnered significant attention in the field of 2D semiconductors for next-generation electronics, spintronics, and photodetector and memristor applications. Currently, BOS is dominantly prepared by chemical vapor deposition and molecular beam epitaxy methods, while pulsed laser deposited (PLD) BOS films are less explored, and the film quality is significantly inferior compared to other preparation methods. In this work, we systematically investigated the PLD growth conditions and defined a growth window (deposition temperature of 340–370 °C and energy density lower than 0.9 J/cm2) for BOS. Atomically flat, high-quality epitaxial and stoichiometric BOS thin films are achieved. Atomic-scale structural and elemental analyses show a unique interfacial region of 2-unit-cell-thick Sr1−xBixTiO3+δ, which accommodates the interfacial strain. The epitaxial BOS film exhibited a Hall mobility of 3103 cm2 V−1 s−1 at 2 K and displayed Shubnikov–de Haas (SdH) oscillations between 2 and 6 K. This observation of SdH oscillations, the first reported for PLD-grown BOS, underscores the high quality of the film. Our work demonstrates the feasibility of enhancing the electrical transport properties of PLD-grown BOS, thereby facilitating future studies in nanoelectronics.