Novel sensor array based on doped tin oxide nanowires for organic vapor detection

A novel sensor array consisting of four types of doped tin oxide nanowires was developed for organic vapor detection. The sensing materials were synthesized into nanowires instead of the traditional thin films to increase the surface-to-volume ratio, and then assembled into sensor units. Four different dopants were used to increase the selectivity of the sensor array, including platinum, copper, indium and nickel. Dynamic and static testing methods were utilized to characterize the performance of the sensor array to eight organic vapors. Results indicated high response of the sensor array in the order of tens of ppb. The investigation on response kinetics revealed fast response/recovery time and good repeatability of the sensor array. A database was compiled from the sensor response of four types of nanowire sensors to different vapor concentration levels. Principle component analysis (PCA) was conducted to reduce the dimensionality of the results and to classify the various organic vapors. PCA plots showed that most of the groups were separable, and hence proved the analyte discrimination capability of the sensor array.