Reduction of Black Gold-Carbon Clusters in Gold Thin Films Deposited by Electron Beam Evaporation

We addressed the problem of black Au-C cluster formation in Au thin films grown by electron beam evaporation. The influence of the electron beam evaporation power on the black-cluster number was investigated.The results show that the electron beam evaporation power significantly affected the deposition rate and number of the black particles. For example, as the electron evaporation power increased in a given range, the deposition rate increased and the number of black particles changed in a decrease-increasemanner, possibly because an increase of the power roseup the liquid Au temperature, and the decreasing surface tension drove the C-impurity to the W-crucible wall and resulted in the so-called " coffee ring effect". We suggest that an optimized“increase-decrease”adjustment ofthe evaporation power in the initial film-growth stage may considerably reduce the number of black particles on Au-film surface.