Ultrahigh Photoresponsivity of Gold Nanodisk Array/CVD MoS$_2$-based Hybrid Phototransistor

TL;DR

This paper demonstrates a hybrid gold nanodisk array and monolayer MoS2 phototransistor with ultrahigh photoresponsivity, significantly outperforming previous MoS2-based photodetectors due to enhanced light-matter interaction.

Contribution

The study introduces a novel AuND/MoS2 hybrid system that achieves record-high photoresponsivity and detectivity, surpassing existing CVD MoS2 photodetectors by leveraging surface trap passivation.

Findings

Achieved photoresponsivity of 8.7×10^4 A/W

Demonstrated specific detectivity of 6.9×10^13 Jones

Observed an order of magnitude improvement over prior MoS2 photodetectors

Abstract

Owing to its atomically thin thickness, layer-dependent tunable band gap, flexibility, and CMOS compatibility, MoS$_2$ is a promising candidate for photodetection. However, mono-layer MoS2-based photodetectors typically show poor optoelectronic performances, mainly limited by their low optical absorption. In this work, we hybridized CVD-grown monolayer MoS$_2$ with a gold nanodisk (AuND) array to demonstrate a superior visible photodetector through a synergetic effect. It is evident from our experimental results that there is a strong light-matter interaction between AuNDs and monolayer MoS$_2$, which results in better photodetection due to a surface trap state passivation with a longer charge carrier lifetime compared to pristine MoS$_2$. In particular, the AuND/MoS$_2$ system demonstrated a photoresponsivity of $8.7 \times 10^{4}$ A/W, specific detectivity of $6.9 \times 10^{13}$ Jones, and gain $1.7 \times 10^{5}$ at $31.84 \mu W/cm^{2}$ illumination power density of 632 nm wavelength with an applied voltage of 4.0 V for an AuND/MoS$_2$-based photodetector. To our knowledge, these optoelectronic responses are one order higher than reported results for CVD MoS$_2$-based photodetector in the literature.