Morphological evolution, luminescence properties and a high-sensitivity ethanol gas sensor based on 3D flower-like MoS2–ZnO micro/nanosphere arrays

Abstract A three-dimensional (3D) flower-like MoS2–ZnO micro/nanosphere array was successfully prepared via a simple two-step synthesis process. The morphology of the samples was characterised using scanning electron microscopy (SEM) and the growth mechanism was elucidated. Raman spectroscopy revealed two intense peaks with enhanced intensity attributed to E 2 g 1 (383.3 cm−1) and A1g (407.1 cm−1) modes of MoS2. The PL spectrum showed an increase in the IUV/IDLE ratio, which indicated that the crystallinity of the sample improved after the MoS2 coating was applied. Gas sensors were fabricated from MoS2–ZnO micro/nanospheres to detect 500 ppm of ethanol at 220 °C. The response and recovery times of the MoS2–ZnO sensor for ethanol gas were 30 s and 10 s, respectively, and the response intensity was 12.08. Compared to pure ZnO, the response and recovery times were shortened by 5s and 6s, and the response intensity was increased by ~6 times. The corresponding gas sensing mechanism was investigated in detail. Our results demonstrate that 3D flower-like MoS2–ZnO micro-nanospheres are expected to be promising for ultra-high gas sensitivity applications.