Resistance response to CO of a film of ZnO NSs at 350°C. The blue solid line shows the resistance versus time curve as various CO concentrations are mixed with the flowing dry air of the test chamber. The decreasing CO concentrations, from 200 to 12.5 ppm, are shown by the dashed red line. The inset shows the response of the sensing film as a function of CO concentration.
Tarat et al. Nanoscale Research Letters 2014 9:11 doi:10.1186/1556-276X-9-11