Long range nanostructuring of silicon surfaces by photonic nanojets from microsphere Langmuir films

International audienceLarge arrays of sub-micrometre blind holes and with a filling ratio up to 60% on areas of millimetre square are realized on silicon. The structuration ensues from combining both Langmuir-Blodgett deposition technique and ultraviolet nanosecond laser-assisted photonic nanojet ablation through C18 functionalized silica microspheres. Different laser fluence ranges and numbers of laser shots are studied to understand the tradeoff between size, quality of the craters and surface morphology after laser irradiation. In particular, tuning the irradiation fluence yields selectivity of the characteristic lateral dimension of the imprinted craters on the substrate and laser operation in multishot mode allows obtaining high quality and regularity of the surface morphology of the resulting millimetre square arrays of holes. This simple, fast, long-range and low-cost near-field nanolithography technique is of interest for fabricating devices with new functionalities and finds applications in many fields in nanoscience and nanoengineering