Optically Controllable 2D Material/Complex Oxide Heterointerface

Heterostructures play a vital role in functional devices on the basis of the individual constituents. Non-conventional heterostructures formed by stacking 2D materials onto structurally distinct materials are of great interest in achieving novel phenomena that are both scientifically and technologically relevant. Here, a heterostructure based on a 2D (molybdenum ditelluride) MoTe2 and an amorphous strontium titanium oxide (a-STO) thin film is reported. The heterostructure functions as a high-performance photodetector, which exhibits anomalous negative photoresponse in the pristine device due to the scattering effect from the light-induced Oδ- ions. The photoresponsivity and the specific detectivity are found to be >104 AW-1 and >1013 Jones, respectively, which are significantly higher than those in standard MoTe2 devices. Moreover, through tuning the light programming time, the photodetection behavior of the MoTe2/a-STO heterostructure experiences a dynamic evolution from negative to positive. This is due to the optically controllable modulation of the interfacial states, which is further confirmed by the X-ray photoelectron spectroscopy and photoluminescence measurements. It is envisioned that the 2D material/a-STO heterostructure could be a potential platform for exploring new functional devices.