In this study we deposited new, ternary thin films of copper aluminum oxide with p-type and n-type
behavior using RF magnetron sputtering for use as chemical gas sensors. p-Type materials are known to
be good catalysts and can be combined with the well-known n-type materials for chemiresistive sensors
application. Copper aluminum oxide in the delafossite phase CuAlO2 is a ternary oxide that has generated
interest as a transparent p-type conducting material, while in the spinel phase CuAl2O4 is known to be
n-type. We demonstrated that thin films of copper aluminum oxide with the proper resistance can be
successfully applied as p- and n-type resistive gas sensors for ozone detection. We have studied the
sputtering deposition conditions from a CuAlO2 sintered target by changing the substrate temperature in
inert Ar atmosphere. In addition, post-deposition annealing in O2 atmospheres was also tested. XRD, SEM
and Raman investigations were used to characterize the thin films. Selected films with mixed phases of
CuAlO2, CuAl2O4 and CuO were tested for gas sensing as resistive chemical sensors, showing promising
results with ozone, acetone and ethanol.