Oxide two-dimensional electron gas with high mobility at room temperature

The prospect of 2-dimensional electron gases (2DEGs) possessing high mobility at room temperature in wide-bandgap perovskite stannates is enticing for oxide electronics, particularly to realize transparent and high-electron mobility transistors. Nonetheless only a small number of studies to date report 2DEGs in BaSnO₃-based heterostructures. Here, we report 2DEG formation at the LaScO₃/BaSnO₃ (LSO/BSO) interface with a room-temperature mobility of 60 cm²/V·s at a carrier concentration of 1.7×10¹³ cm^-2. This is an order of magnitude higher mobility at room temperature than achieved in SrTiO₃-based 2DEGs. We achieved this by combining a thick BSO buffer layer with an ex-situ high-temperature treatment, which not only reduces the dislocation density but also produces a SnO₂-terminated atomically flat surface, followed by the growth of an overlying BSO/LSO interface. Using weak-beam dark field imaging and in-line electron holography technique, we reveal a reduction of the threading dislocation density, and provide direct evidence for the spatial confinement of a 2DEG at the BSO/LSO interface. Our work opens a new pathway to explore the exciting physics of stannate-based 2DEGs at application-relevant temperatures for oxide nanoelectronics.