Effect of the Deposition Temperature on Ammonia Gas Sensing Based on SnO2/Porous Silicon

Enhancing the performance of the room temperature gas sensing that based on a wide surface area of the metal oxide semiconductor is the most important field. In this paper, tin dioxide has been successfully prepared and deposited on the photoelectrochemical etched n-type silicon substrate by spray pyrolysis technique at different deposition temperatures. The constructional, morphological, and topographical properties have been inspected. The XRD patterns showed a broadening peak with a preferential one in the direction (110) having a tiny crystalline size and a huge surface area. The SEM and atomic force microscope displayed semi-spherical microstructures and nanostructures aggregated on the wall of the pores, and the others cover some pores; also, the surface was very rough and has small grains. Sensing characteristics depicted an ultra-response toward ammonia gas at the room temperature with the value of (175%) and quick response and recovery times at the deposition temperature of 350°C. The porous silicon substrate was the ideal way for SnO2 nanoparticles to increase the gas response toward ammonia gas molecules in the humid air.