On-chip synthesis of CuO nanowires for direct gas sensor integration

We report on the direct integration of CuO nanowires into a functional gas sensing device using a simple, cheap and scalable fabrication technology. Our approach relies on thermal oxidation of evaporated copper microstructures for the synthesis of suspended CuO nanowires with very small diameters between 10nm and 30nm at well-defined locations. We operate the devices as conductometric gas sensors and show their sensitivity during exposure to small concentrations of the toxic gases CO (down to 5ppm) and H₂S (down to 10ppb). Due to the promising sensing results and the CMOS backend compatibility of the fabrication process steps, the presented technology may be used for the realization of fully integrated gas sensing devices.