Suspended SnS2 Layers by Light Assistance for Ultrasensitive Ammonia Detection at Room Temperature

Abstract 2D materials are extensively studied as candidates for chemical sensors due to their large surface‐to‐volume‐ratio and the low working temperature. However, the performance of 2D material‐based sensors is limited when detecting ammonia, due to the weak binding between ammonia molecules and channel materials. Previous reports show sensitivity in the ppb range upon NO2 exposure, and in ppm levels of ammonia under the same conditions. Compared with the traditional SnS2 sensors, the demonstrated suspended devices with light excitation exhibit a higher sensitivity, a faster response, and recovery rate. At room temperature, the devices show obvious response to NH3 vapor at a concentration as low as 20 ppb. High selectivity to ammonia over many other chemical gases is observed. Such arresting features originate from the suspended structure enhancing reaction area and the light excitation inducing increased charge density that facilitates the ammonia detection. The enhanced sensing performance demonstrates the superiority of the suspended structure with light assistance, and this method can be applied to other 2D material‐based sensors on optimizing their performance.