Fabrication and characterization of size-selected Cu nanoclusters using a magnetron sputtering source

Copper nanoclusters are used widely in applications such as glucose and gas sensors. A physical method is used to produce copper nanoclusters utilizing an ultra-high vacuum (UHV) system. Using a quadrupole mass filter (QMF), the size distribution of the nanoclusters is determined. It is found that varying the source parameters controls the size of the produced Cu nanoclusters. Increasing the aggregation length increases the nanocluster size. Varying the inert gas flow rate has a minor effect on the size at low aggregation length. On the other hand, at high aggregation length the size increases with increasing the gas flow. The results are interpreted in terms of the nucleation time and a two-body collision model between nanoclusters. Moreover, the band gap is measured for different sizes of CuO nanoclusters.