Wafer-Scale Growth of Single-Crystal 2D Semiconductor on Perovskite Oxides for High-Performance Transistors

Emerging two-dimensional (2D) semiconducting materials serve as promising alternatives for next-generation digital electronics and optoelectronics. However, large-scale 2D semiconductor films synthesized so far are typically polycrystalline with defective grain boundaries that could degrade their performance. Here, for the first time, wafer-size growth of a single-crystal Bi2O2Se film, which is a novel air-stable 2D semiconductor with high mobility, was achieved on insulating perovskite oxide substrates [SrTiO3, LaAlO3, (La, Sr)(Al, Ta)O-3]. The layered Bi2O2Se epilayer exhibits perfect lattice matching and strong interaction with perovskite oxide substrates, which enable unidirectional alignment and seamless mergence of multiple seeds into single-crystal continuous films free of detrimental grain boundaries. The single-crystal Bi2O2Se thin films show excellent spatial homogeneity over the entire wafer and allow for the batch fabrication of high-performance field-effect devices with high mobilities of similar to 150 cm(2) V-1 s(-1) at room temperature, excellent switching behavior with large on/off ratio of >10(5), and high drive current of similar to 45 mu A mu m(-1) at a channel length of similar to 5 mu m. Our work makes a step toward the practical applications of high-mobility semiconducting 2D layered materials and provides an alternative platform of oxide heterostructure to investigate novel physical phenomena.