Ozone sensing using In/sub 2/O/sub 3/-modified Ga/sub 2/O/sub 3/ thin films

It is shown that at elevated temperatures the conductance of an In/sub 2/O/sub 3/-modified Ga/sub 2/O/sub 3/ thin film depends significantly and reversibly on the ozone concentration in the ambient air. This ozone sensitivity is much greater than with pure Ga/sub 2/O/sub 3/ or In/sub 2/O/sub 3/ thin films, respectively. The ozone sensitivity of the In/sub 2/O/sub 3/-modified Ga/sub 2/O/sub 3/ thin film is characterized by an impressive selectivity, and is maximal at an operation temperature of about 600/spl deg/C. The cross sensitivities to other gases present in ambient conditions are small compared to the ozone sensitivity, thus opening the way to use this system for ambient ozone monitoring. The results are discussed using an electron injection model.