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

Abstract 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.