Effect of dendrite structures on gas sensing properties in in-doped SnO2 thin films

Enhanced sensing response for NO2 gas has been observed in In-doped SnO2 (ITO) thin films deposited by sol gel spin coating process on glass substrates. These films show micron size dendrite structures, which are considered to be responsible for enhanced sensitivity. The density of dendrite structures increases with increase in dopant concentration. 10 wt% In-doped thin films show maximum sensitivity. EDX studies of these dendrites reveals Indium at their edges and center. The growth of these structures is based on the concept of supersaturation. The effect of dendrites in In-doped tin oxide films is explained based on deposition kinetics and crystal habits of the system.