Two-Dimensional Electron Gases at LaAlO₃/SrTiO₃ Nanostructured Heterointerfaces with a Buffering Layer for Oxide-Based Electronics

We investigate the transport and photoresponsive properties at nanostructured LaAlO3/SrTiO3 interfaces by a (La0.3Sr0.7)(Al0.65Ta0.35)O3 buffering layer which produces a gradient strain. It is interesting that the buffering layer increases the critical thickness and enhances the carrier mobility for metallic samples. Moreover, these samples show a strong dependence of photoresponse on the thicknesses of LaAlO3 films. In particular, an irreversible photoinduced insulator-to-metal transition is achieved at LaAlO3 (1.6 nm)/(La0.3Sr0.7)(Al0.65Ta0.35)O3 (0.4 nm)/SrTiO3 interfaces. Our results provide an effective approach to modulate the transport and photoresponsive properties and are also of great significance for designing optoelectronic devices based on oxide electronics.