Giant enhancing photoresponse at LaAlO3/SrTiO3 interfaces by the nickelate buffer layer

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.

Manipulating Spin–Orbit Coupling at Oxide Interfaces by Lanthanum Cobaltate

“…For examples, Zhang et al reported a magnetic 2DEG at a La 7/8 Sr 1/8 MnO 3 -buffered LAO/STO interface, while a high-mobility 2DEG exceeding 10 000 cm 2 V –1 s –1 at 2 K was declared by inserting La 1– x Sr x MnO 3 at LAO/STO interfaces . We also observed an enhanced photoresponse by 5 orders using the insertion of a NdNiO 3 buffer layer at LAO/STO interfaces . Therefore, it is necessary to study the influence of different thicknesses of buffer layers on a 2DEG.…”

“…Moreover, the 2DEGs exhibit a very sensitive response to external stimuli, like light, electric field, ionic liquid, etc., suggesting potential in electronic and optical devices. ,− Recent studies have shown that introducing buffer layers at interfaces effectively modifies the crystal and electronic structure, thus manipulating the characteristics of a 2DEG, especially the photoconductivity, , carrier mobility, and magnetic properties . In addition, the different thicknesses of the buffer layer also can tune the transport properties at the interface, such as the metal-insulation transition, photoresponse, , and relaxation time constant . For examples, Zhang et al reported a magnetic 2DEG at a La 7/8 Sr 1/8 MnO 3 -buffered LAO/STO interface, while a high-mobility 2DEG exceeding 10 000 cm 2 V –1 s –1 at 2 K was declared by inserting La 1– x Sr x MnO 3 at LAO/STO interfaces .…”

“…27 We also observed an enhanced photoresponse by 5 orders using the insertion of a NdNiO 3 buffer layer at LAO/STO interfaces. 28 Therefore, it is necessary to study the influence of different thicknesses of buffer layers on a 2DEG. Consequently, inserting magnetic oxides on the atomic scale will produce more attractive effects at the LAO/STO interfaces due to the broken space-reversal symmetry.…”

Manipulation of 2DEG at double-doped high-entropy heterointerfaces

“…[14][15][16][17][18][19][20][21][22][23] These complex oxide interfaces provide combined efficiency of different factors, like crystal lattice, orbital, and spin, [24][25][26] which explain the diversity of physical phenomena and sensitive response towards external stimuli. To manipulate the 2DEG in such oxide interfaces, some research studies have adopted different doping methods, like structural modulation by introducing a buffer layer, [27][28][29][30][31][32] and they proved their good capability. However, the discontinuity in the structure and component can naturally lead to some limitations, like localized trap or scattering centers for carriers.…”

Enhanced Rashba Spin Orbit Coupling and Magnetic Behavior at Oxide Heterointerfaces by Optical Gating

“…Two-dimensional electron gas (2DEG) at the interface of insulating complex oxides has been drawing tremendous attention ever since its first report by Hwang et al at the interface of LaAlO 3 (LAO) and SrTiO 3 (STO). Such 2DEG shows a lot of significant phenomena, like superconductivity, high carrier mobility, magnetism, Rashba spin–orbit coupling ( SOC ), and sometimes coexistence of them, − forming a complex system of quantum coherence that responds to multiple external stimuli. Among these appealing properties of interfacial 2DEG, the magnetism is a strongly desired one, , as it provides a powerful platform to study the spintronics in all-oxide devices. − To date, there have been many meaningful works to generate magnetic 2DEGs at the interfaces of complex oxides, like to use a magnetic substrate or capping layer, , to introduce magnetic dopants, , or to insert a magnetic buffer layer into the interface. − These works broaden our horizon in condensed matter physics.…”