High-Responsivity and Broadband MoS 2 Photodetector Using Interfacial Engineering.

Combining MoS 2 with mature silicon technology is an effective method for preparing high-performance photodetectors. However, the previously studied MoS 2 /silicon-based heterojunction photodetectors cannot simultaneously demonstrate high responsivity, a fast response time, and broad spectral detection. We constructed a broad spectral n-type MoS 2 /p-type silicon-based heterojunction photodetector. The SiO 2 dielectric layer on the silicon substrate was pretreated with soft plasma to change its thickness and surface state. The pretreated SiO 2 dielectric layer and the silicon substrate constitute a multilayer heterostructure with a high carrier concentration and responsiveness. Taking silicon-based and n-type MoS 2 heterojunction photodetectors as examples, its responsivity can reach 4.05 × 10 4 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 MoTe 2 , ReS 2 , etc., with certain versatility.