Light absorption with branched gold cauliflower-like nanostructure arrays

• Growth of branched gold (Au) cauliflower shaped nanoparticles on Cicada's wing nanonipple arrays is reported.
• Optical properties of these branched gold nanostructure arrays show reduction of light reflection and enhance light trapping.
• This branched structure can be used in Photovoltaic devices to enhance their performance.

In the present study, we have investigated the growth of branched gold (Au) cauliflower-shaped nanoparticles on Cicada's wing nanonipple arrays. The gas aggregation dc magnetron sputtering nanocluster source without size filtration was employed for fabrication of the samples. It was observed that the operating conditions of dc magnetron sputtering, such as gas pressure in the aggregation chamber and discharge power, control the deposition of charged clusters. By changing the operational conditions, a nanocauliflower-like (NCF) structure grew on the nanonipples. This Au nanostructure with a cauliflower-shaped surface feature was monitored using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The optical properties of these branched gold nanostructure arrays were also studied. Reduction of light reflection and the consequent light trapping suggest use of this branched structure for achieving broadband light absorption in Plasmonic solar cells as a result of plasmonic effects.