Growth dynamics of pulsed laser deposited nanofoams

Abstract

We present a modeling and experimental investigation about the physics of nanofoam growth in pulsed laser deposition (PLD) experiments. Thanks to their unique features, ultralow density materials---known as nanofoams---are attracting a growing interest for many cutting-edge applications. PLD has emerged as one of the most promising and versatile techniques for the synthesis of nanofoam; however, the lack of a satisfactory comprehension of the nanofoam growth process hinders the unleashing of their full potential as innovative materials. In this work we propose a snowfall-like model that describes the nanofoam growth as the coalescence of micrometric-sized fractal aggregates of nanoparticles, where the aggregates are formed through an in-flight process whose timescale is determined by the shot-to-shot time interval. We exploit these insights to demonstrate an approach to control the nanofoam properties down to the nanoscale. These results, along with their interest from a fundamental point of view, open perspectives in the field of low density nanostructured materials.