Gold nanoparticles incorporated SnO2 thin film: highly responsive and selective detection of NO2 at room temperature

A facile and two-step procedure, sputtering followed by annealing, was adopted to achieve highly dispersed gold nanoparticles on SnO2 film. Morphological observations revealed that the gold nanoparticles were uniformly dispersed over the surface of SnO2 film. The transmittance and crystallinity of the as-fabricated film was found to improve substantially after the heat treatment. The suitability of the as-fabricated thin film for gas sensing was tested by detection of NO2. The results showed high response, and selectivity towards NO2. The response was about 90% to 50 ppm NO2 at room temperature, which was 5.5 and 3.2 times higher than that of the gold layer loaded SnO2, and pristine SnO2 sensors, respectively.