Improvement of photoelectric properties of MoS2/WS2 heterostructure photodetector with interlayer of Au nanoparticles

A novel structure of photodetector with a higher optoelectronic response is fabricated based on MoS2/Au NPs/ WS2 heterostructure in this work. Here, contact of Au nanoparticle (Au NPs) with MoS2 and WS2 can form n-type barrier layers that suppress the dark current of the device. On the other hand, the optical field intensity near the Au NPs is increased due to the local surface plasmon resonance of Au NPs which promotes the absorption of light by MoS2 and WS2 and then increases the photocurrent without changing the dark current of the device. By comparing the performance of the MoS2/WS2 heterojunction photodetector, we found that the photoelectric properties (such as Responsivity, External Quantum Efficiency, and ON/OFF ratio) of the MoS2/Au NPs/WS2 photodetector are almost ten times higher or more. This method of integrating Au NPs in heterojunction provides a solution for heterojunction optoelectronic devices with poor responsivity, paving the way for the performance improvement of highly freely matched two-dimensional material heterojunction photodetectors.