No abstract

Manipulating the photoresponse of two-dimensional electron gas at the interface of complex oxides is attracting tremendous interest because of its potential applications in photoelectric devices. In this study, transport behaviors of LaAlO3/SrTiO3 heterointerfaces tuned by a nickelate buffer layer under light irradiation have been investigated. With the increasing thickness of the buffer layer, the LaAlO3/SrTiO3 interfaces exhibit the metal-to-insulator transition. More importantly, we also observe a substantial enhancement in the photoresponse under a 360 nm light irradiation and the relative change in the resistance of heterointerfaces is enhanced from 6.8% (without a buffer layer) to 50 139% (with a 1.6 u.c. buffer layer) at 300 K. Moreover, the heterointerfaces exhibit a state of change from persistent to transient photoconductivity. These emerging results are analyzed in view of the relevant mechanisms of band bending and lattice effects. This work provides experimental support for the application of perovskite oxides in interface optoelectronics.

The photoinduced phase transition at complex oxides remains one of the very important issues because of the emergent physics and potential applications. In particular, the mechanism of charge transfer at interfaces under irradiation is challenging. Herein, the photoinduced properties of manganite-buffered LaAlO 3 /SrTiO 3 interfaces with different thicknesses of the buffer layer are systematically investigated. The giant photoresponse is observed, and its relative change in resistance is about 6.24 × 10 6 % at T = 20 K for the sample with a buffer layer thickness of 4.8 nm. Moreover, the transition temperature is enhanced by increasing the thickness of the buffer layer. More importantly, the dead layer effect at the interfaces has been suppressed by using light. All these results are attributed to the charge transfer because of the octahedral tilting at low temperatures and provide a new kind of oxide-based optical devices, such as ultraviolet detectors. This piece of work will pave the way toward twodimensional electron gas-based optoelectronic devices.