Silicon bump arrays by near-field enhanced femtosecond laser irradiation in fluorine liquid precursors

► A simple approach to fabricate periodic array of conical bumps on silicon (Si) substrate is reported. ► The influence of the medium on the near-field interactions for both sizes silica particles layer is investigated. ► By varying the sizes for the colloidal particles, i.e. 700 nm and 390 nm, we were able to tune, in the near field, the surface density of the Si bumps. ► The developed Si nanobump pattern has potential applications for sensitive detectors, efficient photovoltaic cells, field emitter arrays and displays.