Plasma-Enhanced Interfacial Electric Field for High-Performance MoS2/p-Si Photovoltaic Photodetectors

Abstract

Localized surface plasmon resonance (LSPR) has the characteristics of a local electromagnetic field enhancement, which is extremely important in developing miniaturized high-performance photodetectors (PDs). However, most LSPR effects are used to improve the light absorption of PDs, while the incidental problem of slow response speed is often ignored. Here, we designed to construct a strong built-in electric field (BEF) within the heterojunction to solve this problem. This work demonstrates an Au@MoS₂/p-Si photovoltaic PD with both high responsivity and fast response speed. Noticeably, Au nanoparticles (Au NPs) integrated on the MoS₂ surface can induce LSPR to pass through monolayer MoS₂ (1L-MoS₂) to enhance the interfacial BEF of MoS₂/p-Si, as confirmed by finite-difference time-domain simulations. Our device demonstrates simultaneous improvements in both photoresponse and response speed without sacrificing the interface quality. The photovoltaic PD exhibits excellent performance with a responsivity of 1498 mA/W, a detectivity of 1.96 × 10¹² Jones, and an ultrafast response time of 3 μs, respectively. This work realizes the possibility of LSPR to enhance the interfacial BEF of heterojunctions and extends its application field to high-performance plasmonic PDs.