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

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 $31.84\mu W/c{m}^2$ 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.

30 pages, 14 figures