NO2 detection by adsorption induced work function changes in In2O3 thin films

A potentiometric sensor platform has been used for NO2 detection at room temperature by measuring the adsorption induced surface work function changes in In2O3 thin films deposited on Si using a solution based process. The highly resistive films were unsuitable for amperometric detection of NO2; however, significant work function changes of similar to 30 mV were measured for similar to 50 s of exposure to 70 ppm NO2, and detection down to 600 ppb (parts per 10(9)) was possible. A model for the transient response was developed, which satisfactorily fits the experimental data. Acceleration of the desorption transient under ultraviolet illumination has also been investigated. (C) 2007 American Institute of Physics.