High-Responsivity and Broadband MoS₂ Photodetector Using Interfacial Engineering

Combining MoS₂ with mature silicon technology is an effective method for preparing high-performance photodetectors. However, the previously studied MoS₂/silicon-based heterojunction photodetectors cannot simultaneously demonstrate high responsivity, a fast response time, and broad spectral detection. We constructed a broad spectral n-type MoS₂/p-type silicon-based heterojunction photodetector. The SiO₂ dielectric layer on the silicon substrate was pretreated with soft plasma to change its thickness and surface state. The pretreated SiO₂ dielectric layer and the silicon substrate constitute a multilayer heterostructure with a high carrier concentration and responsiveness. Taking silicon-based and n-type MoS₂ heterojunction photodetectors as examples, its responsivity can reach 4.05 × 10⁴ A W^1- at 637 nm wavelength with a power density of 2 μW mm^-2, and the detectable spectral range is measured from 447 to 1600 nm. This pretreated substrate was proven applicable to other n-type TMDCs, such as MoTe₂, ReS₂, etc., with certain versatility.