CuO Nanowire Humidity Sensors Enhanced by Au Nanostructure Prepared on TSV Substrate

The authors studied the growth of cupric oxide nanowires (CuO NWs) on through-silicon via (TSV) substrates and the subsequent fabrication of humidity sensors utilizing these CuO NWs. We also explored the effect of annealing gold nanoparticles (Au NPs) deposited on CuO NWs through sputtering with varying thicknesses of the Au film (1–5 nm) to enhance the humidity response. The morphology and crystallography of both CuO NWs and Au NPs were characterized using multi-function environmental field-emission scanning electron microscopy and X-ray diffraction techniques. The results indicate that the resistance of the CuO NWs increased with increasing relative humidity, attributed to the p-type conductivity of CuO. Adding the Au NPs further augmented the humidity response. Interestingly, an increase in the initial thickness of the Au film led to a proportional increase in the average diameter of the annealed Au NPs, ranging from 11 to 31 nm for Au film thicknesses of 1–5 nm. Notably, the sample with 11 nm Au NP/CuO NWs exhibited superior sensor response compared to the samples of other thicknesses.