Thin films of MoO3 for gas sensing applications have been deposited by
reactive sputtering using a metallic molybdenum target. After anneali
ng at 500 degrees C in air, the layers consist of rhombic molybdenum t
rioxide with a (010) texture. The morphology of the layers considerabl
y depends on the film thickness. Electrical conductivity measurements
with different test gases show that MoO3 layers are suitable for NH3 d
etection at operating temperatures between 400 and 450 degrees C.