Large and Uniform Single Crystals of MoS2Monolayers for ppb-Level NO2Sensing

Abstract

Recently, unprecedented interest has been immersed toward the synthesis of two-dimensional (2D) transition metal dichalcogenides via the chemical vapor deposition (CVD) system. Synthesis of a uniform and large-sized monolayer MoS<inf>2</inf>atomic thin film via CVD is still a major bottleneck owing to strong dependence on diverse associated growth parameters. In this work, we have proposed the most viable recipe which is suitable for controlling the nucleation density of Mo and producing a 90 μm-long MoS<inf>2</inf>monolayer crystal and (695 × 394.8) μm2large MoS<inf>2</inf>monolayered film on SiO<inf>2</inf>/Si and c-plane sapphire, respectively. Moreover, MoS<inf>2</inf>monolayer sensing performance has been thoroughly investigated for NO<inf>2</inf>exposure at room temperature with a varying response of 4-57.5 for the 100-100 ppm level. Furthermore, the MoS<inf>2</inf>monolayer sensor exhibits an ultrasensitive NO<inf>2</inf>detection with limit of detection and limit of qualification values of 1.4 and 4.6 ppb, respectively. In addition, the first-principles-based density functional theory has been employed to analyze the adsorption of NO<inf>2</inf>on the surfaces of the 2D MoS<inf>2</inf>monolayer. It is observed that the electronic band gap of the MoS<inf>2</inf>monolayer after NO<inf>2</inf>adsorption is reduced by 0.7 eV due to molecular orbital hybridization. © 2022 American Chemical Society. All rights reserved.