Photoresponsive properties at (0 0 1), (1 1 1) and (1 1 0) LaAlO₃/SrTiO₃ interfaces

We report the photoresponsive characteristics of (0 0 1), (1 1 0), and (1 1 1) LaAlO₃/SrTiO₃ heterointerfaces deposited at different oxygen pressures using a 360 nm light. The results show that LaAlO₃/SrTiO₃ interfaces with less oxygen vacancies exhibit a larger resistance change when illuminated by light and a slower recovery process when light is off. In addition, the (1 1 0) LaAlO₃/SrTiO₃ heterointerfaces present the smallest photoinduced change and residual photoinduced change in the resistance, which are related to the negligible polarization discontinuity at the interfaces. Our results provide a deeper insight into the photoinduced properties in the 2D electron gas system, paving the way for the design of oxide optoelectronic devices.