Effect of interdiffusion on electrical and gas sensor properties of CuO/SnO2 heterostructure

The influence of annealing on the electrical and H2S gas sensor properties of p-CuO/n-SnO2 heterostructures has been investigated. The heterostructures were prepared by magnetron sputtering technique with subsequent oxidation. The depth composition was analyzed by the secondary neutral mass-spectrometry (SNMS) method. The Sn and Cu interdiffusion coefficients at 573 K were estimated as 3×10−14 cm2 s−1 and 1×10−15 cm2 s−1, respectively. Resistance behavior and high H2S gas sensitivity are associated with the formation of a transitional layer at CuO–SnO2 interface due to interdiffusion processes.