Using CuO polycrystalline nanofilms as sensor for small organic molecules

The presentation will be focused on exploring the use of the thermal evaporation technique for fabrication of copper and copper oxide nanofilms, the latter addressed to be used as sensors of small organic molecules. The nanofilm’s thickness control is achieved through modulation of the Z-position (metal source-to-substrate distance) within the chamber. It is found that the grain size ( ? ) is strongly correlated with the film thickness (ω), being described by a power law ( ? ∝ ?%), where n is around 0.5 for the as-fabricated copper nanofilms. Measurements reveal resistivity ranging in the range of 3 to 5 µΩ´cm for the copper nanofilms, aligning closely with expectations for copper nanofilms composed of crystallites sized between 20 and 30 nm, which is consistent with the grain sizes obtained from x-ray diffraction (XRD) data. In order to produce copper oxide nanofilms, thermal annealing process was carried out at 200°C in air for 20 hours. XRD data analysis indicates mean crystallite sizes varying from about 9 nm up to about 24 nm as the nanofilm’s thickness increases. Electrical measurements indicate a p-type copper oxide semiconductor, with carrier concentrations of around 1014 cm-3, which shows a slight decrease as the nanofilm’s thickness increases.