An ultrafast MoTe2-based photodetector via MoO3 interface layer optimization

Two-dimensional (2D) molybdenum ditelluride (MoTe2) has attracted wide attention due to its unique crystal structure and outstanding optical and electrical properties in photodetection. However, as a bipolar material, MoTe2 is more sensitive to environmental factors compared to other 2D materials. Interface issues in MoTe2 devices severely affect their photodetection performance. Here, we focus on improving the material and dielectric interface and propose a highly sensitive photodetector based on a MoO3-MoTe2 heterostructure. Through interface engineering, MoO3 not only serves as a substrate dielectric layer to improve the material and dielectric interface but also forms a heterostructure with MoTe2, inducing charge transfer and realizing a p-n junction with a large built-in electric field. Due to these characteristics, the device exhibits excellent photodetection performance with an open-circuit voltage Voc = 0.46 V and short-circuit current Isc = 210nA. In 532 nm self-powered mode, the responsivity of the device is 2 mA /W, with a light-to-dark ratio of approximately 105, rise/decay times of 78/49 μs, and a cutoff frequency exceeding 7 kHz. This work provides inspiration for the future development of high-performance photodetectors, with MoO3 as a substrate showing promise for achieving high optical responsivity and fast response in 2D material photodetectors.