Metal-oxide (MOx) nanowire (NW) based gas sensors have proven to be highly sensitive to different gases due to their high surface-to-volume ratio. This sensitivity restricts the MOx capacity to distinguish between different gases. To overcome this shortcoming, noble metal nanoparticles (NPs) deposited on MOx NWs increases the sensitivity and selectivity of the gas sensor . In previous work , single CuO NWs were functionalized by 5nm Pd NPs to increase carbon monoxide (CO) sensing. While the size effect of metallic NPs on gas sensing performance has already been intensively investigated in literature , there are only few reports on the metallic NP coverage effect, especially on CuO NW based gas sensors. Thus, in this work, CuO NW devices were decorated with different amounts of size-selected Pd NPs using a cluster beam deposition (CBD) method based on magnetron sputtering processes. This allows us to study the coverage effect on the sensing performance towards different gases. Also, this study provides an insight for the optimum coverage needed to functionalize CuO NWs and enhance their sensitivity and selectivity.
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