Synthesis, Characterization and Gas Sensing Properties of Ga-Doped SnO2 Nanostructures

In this work influence of Ga-doping on the sensor response and selectivity of SnO2 based sensors has been investigated in detail. The effect of in-plane and bridging oxygen vacancies on the gas sensing properties of SnO2 has also been investigated. Raman and photoluminescence results revealed that defect concentration increases with increase in Ga concentration. A Brunauer–Emmett–Teller (BET) study disclosed that specific surface area increases with increase in Ga content. It has been observed that Ga-doped SnO2 nanostructures exhibited temperature dependent selectivity towards acetone and hydrogen. It is found that a 3% Ga-doped SnO2 based sensor is selective to acetone at 200°C while it is selective to hydrogen at 300°C. The observed temperature dependent selectivity of 3% Ga-doped SnO2 might be due to its different catalytic properties towards acetone and hydrogen. The increased surface area and abundant in-plane oxygen vacancies of Ga-doped SnO2 samples provided an enhanced sensor response towards 100 ppm of acetone and hydrogen, respectively. The influence of particle size on the intergranular activation energy has been investigated as well.