Amorphous Nitride and Fluoride Film-Induced Two-Dimensional Electron Gas at SrTiO3-based Heterojunction Interfaces

Two-dimensional electron gas (2DEG) at oxide interfaces is of great interest in solid state research. Here, 2DEG was shown to form at amorphous-BN/SrTiO3 and amorphous-LaF3/SrTiO3 interfaces and have similar properties to 2DEG at traditional oxide interfaces. Because of film chemical properties, the growth atmosphere and air clearly influenced 2DEG at these interfaces. With x-ray photoelectron spectroscopic measurements, anion diffusion between the film and the substrate existed, but they appeared not to be the reason for 2DEG formation. Furthermore, these findings suggested that amorphous film-induced interfacial conductivity might be a common phenomenon that should be considered in the study of heterojunctions.