An Ultrasensitive Gateless Photodetector Based on the 2D Bilayer MoS₂–1D Si Nanowire–0D Ag Nanoparticle Hybrid Structure

Abstract

Atomically thin transition metal dichalcogenides (TMDC) have received much attention due to their wide variety of optical and electronic properties. Among various TMDC materials, molybdenum disulfide (MoS₂) has been intensely studied owing to its potential applications in nanoelectronics and optoelectronics. However, two-dimensional MoS₂ photodetectors suffer from low responsivity due to low optical cross section. Combining MoS₂ with plasmonic nanostructures can drastically increase scattering cross section and enhance local light-matter interaction. Moreover, suspended MoS₂ has been shown to exhibit higher photoluminescence intensity and strong photogating effect, which can be employed in photodetectors. Herein, we propose an approach to utilize plasmonic nanostructures and physical suspension for 2D MoS₂ photosensing enhancement by hybridizing 2D bilayer MoS₂, 1D silicon nanowires, and 0D silver nanoparticles. The hybrid structure shows a gateless responsivity of 402.4 A/W at a wavelength of 532 nm, which represents the highest value among the ever reported gateless plasmonic MoS₂ photodetector. The great responsivity and large active area results in an exceptional detectivity of 2.34 × 10¹² Jones. This study provides a new approach for designing high-performance 2D TMDC-based optoelectronic devices.