Improved NH3 Gas Sensing Performance of Femtosecond-Laser Textured Silicon by the Decoration of Au Nanoparticles

The escalating environmental concerns have stimulated the demand for NH3 gas sensors, which are indispensable for real-time data collection in pollution monitoring. To address this need, optimized NH3 sensor based on femtosecond-laser textured silicon decorated with Au nanoparticles (Au-NP) is designed. The morphologies and microstructures of the fabricated samples are characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) technologies. The gas-sensing results demonstrated that the modification of Au-NPs significantly enhances the NH3 gas-sensing performances. Specifically, the sensor based on the textured silicon decorated with Au NPs exhibits a remarkable response of 16.02% toward 20 ppm NH3, which is 4.7 times higher than that of the pristine textured silicon gas sensor at room temperature. In addition, it also demonstrates shortened response and recovery time (26 s/98 s), showing good selectivity and long-term availability. The enhanced NH3-sensing mechanism of the sensor is elucidated, mainly due to the synergistic effect of textured silicon and Au NPs. These contribute to the development of portable, wearable, and intelligent sensor equipment.