Room Temperature Ammonia Gas Selectivity Studies On SnO2 Ultra Thin Film Prepared By Langmuir-Blodgett Technique

Interaction of various reducing and oxidizing gases with ultrathin SnO(2) film at room temperature has been studied to investigate the selectivity of SnO(2) film towards ammonia. SnO(2) thin films show no response with O(2), H(2), CO, ethanol and methane. In presence of H(2)S and SO(2) gases conductivity of the film increases where as film conductivity decreases with ammonia and NO(2). With ammonia gas, the response is fast and > 90% recovery takes place within 30 min where as with NO(2)_recovery is partial. The impedance study shows distinctly different frequency dependent responses towards NH(3) and NO(2) indicating specificity to ammonia in presence of NO(2).