High-Performance Volatile Organic Compounds Microsensor Based on Few-Layer MoS₂-Coated Photonic Crystal Cavity

Detection of volatile organic compounds (VOCs) is extremely important for industrial and human safety. Here, a high-performance optical microsensor is demonstrated for VOCs detection using a photonic crystal (PC) cavity integrated with a few-layer molybdenum disulfide (MoS₂) flake. Because of the strong interactions between the cavity's evanescent field and the coated VOCs-sensitive MoS₂ layer, the resonant wavelength of the PC cavity exhibits distinct responses toward VOCs. The MoS₂-PC cavity microsensor presents good capability to identify different vapor concentrations and has a good repeatability. In particular, the compact structure, thin MoS₂ flake and possible presence of chemisorption with oxygen-containing VOCs species promise a fast response time of 300 ms. The sensor's high selectivity for specific VOCs is validated as well. Comparing to the electrically driven VOCs-sensors based on 2D layered materials, the proposed sensor has advantages of compact size, easy fabrication, mass production, and simply optical access.