Sensing of ammonia gas by undoped and aluminum-doped tin oxide nanoparticles by Raman spectroscopy

The study of gas sensing properties of SnO 2 has been widely carried out mainly using electrical methods where a change in resistance or / and conductance of SnO 2 is measured when it is exposed to the sample. In this work, a spectroscopic approach was employed using Raman intensity as a tool to study the sensing of ammonia by undoped and aluminum-doped SnO 2 nanoparticles. The study showed a variation of intensity of the classical Raman modes of SnO 2 , when SnO 2 was exposed to ammonia. The response to ammonia by nanoparticles of different sizes and doping concentrations was calculated. This study also revealed the optimum crystallite size and doping concentration suitable for sensing ammonia. However, the most important conclusion that could be drawn from this study was that the response of SnO 2 to ammonia could be detected at room temperature through Raman spectroscopy unlike in the case of electrical studies, where a high temperature is required for sensing.