Gap‐Mode Surface‐Plasmon‐Enhanced Photoluminescence and Photoresponse of MoS 2

2D materials hold great potential for designing novel electronic and optoelectronic devices. However, 2D material can only absorb limited incident light. As a representative 2D semiconductor, monolayer MoS 2 can only absorb up to 10% of the incident light in the visible, which is not sufficient to achieve a high optical‐to‐electrical conversion efficiency. To overcome this shortcoming, a “gap‐mode” plasmon‐enhanced monolayer MoS 2 fluorescent emitter and photodetector is designed by squeezing the light‐field into Ag shell‐isolated nanoparticles–Au film gap, where the confined electromagnetic field can interact with monolayer MoS 2 . With this gap‐mode plasmon‐enhanced configuration, a 110‐fold enhancement of photoluminescence intensity is achieved, exceeding values reached by other plasmon‐enhanced MoS 2 fluorescent emitters. In addition, a gap‐mode plasmon‐enhanced monolayer MoS 2 photodetector with an 880% enhancement in photocurrent and a responsivity of 287.5 A W −1 is demonstrated, exceeding previously reported plasmon‐enhanced monolayer MoS 2 photodetectors.