Combinatorial libraries of semiconductor gas sensors as inorganic electronic noses

We have fabricated thin-film combinatorial gas sensor libraries based on doped semiconducting SnO2 thin films. Combinatorial pulsed-laser ablation was used to deposit compositionally varying arrays of sensor elements onto a prepatterned device electrode configuration. Using multiplexing electronics, we have demonstrated the detection of chloroform, formaldehyde, and benzene gases at concentrations down to 12.5 ppm through pattern recognition of signals from the arrays of sensors. This technique of fabricating gas sensor arrays as combinatorial libraries can be applied to the manufacturing of portable electronic noses.