Heterostructured p-CuO (nanoparticle)/n-SnO2 (nanowire) devices for selective H2S detection

Dihydrogen sulphide (H2S) is a dangerous pollutant released in fossil combustion processes. Here, p-CuO (particle)/n-SnO2 (nanowire) heterostructures were evaluated as selective H2S sensors, and the working principle behind their good performance was qualitatively modelled. It was concluded that the main sensing mechanism was dissimilar to standard redox reactions typical of simple metal oxide devices, but ascribable to the sulphurization of CuO and the consequent variation of the pn-junction band structure at the CuO–SnO2 interfaces. Experimental data showed that these H2S sensors suit well for alarm applications with extremely high selectivity and sensitivity to this gas for concentrations between 1 ppm and 10 ppm.