Hydrogen sulphide detection by CMOS integrated tungsten oxide nanowire networks

Metal oxide nanostructures like tungsten oxide nanowires are intensively studied materials for sensor applications. In this work we report on tungsten oxide gas sensors integrated on a CMOS fabricated microhotplate chip. Tungsten oxide gas sensors were prepared by drop coating of a nanowire network suspension onto interdigitated electrodes prefabricated on the CMOS microhotplate chip. The tungsten oxide nanowire network was characterised by TEM and Raman spectroscopy, confirming their non-stoichiometric state. Using tungsten oxide nanowire networks as gas sensing material we observed high sensitivity to hydrogen sulphide: concentrations of 1 ppm have been detected with a sensor response up to 55%.