Fractal Carbon nanofoams by nanosecond and femtosecond pulsed-laser deposition

TL;DR

This paper investigates the properties of ultra-low density fractal carbon nanofoams produced by pulsed-laser deposition, analyzing how process parameters influence foam structure and density, and proposing a predictive analytical model.

Contribution

It introduces an analytical equation based on fractal scaling laws to predict foam density from aggregate properties, aiding controlled fabrication.

Findings

Foam density varies with background gas pressure and laser pulse characteristics.

An analytical model successfully predicts foam density from fractal aggregate properties.

Process parameters influence nanofoam growth and structure, guiding experimental fabrication.

Abstract

We report on an investigation on the properties of ultra-low density, fractal, Carbon nanofoams fabricated with the nanosecond and femtosecond pulsed-laser deposition (PLD) techniques. We measure through innovative techniques the foam mean density and the properties of the fractal aggregates composing the film (i.e. nanoparticles diameter, fractal dimension, and gyration radius) as a function of several PLD process parameters, namely the background gas pressure and the laser pulse characteristics (energy, time duration, repetition rate). We discuss the experimental observation on the basis of the existing literature, and we propose an analytical equation, based on the fractal scaling law, to predict the foam density from the aggregates properties. Finally, we use analytical arguments to explain the observed trends in the nanofoam density with respect to the process parameters, useful to gain new insights on the nanofoam growth and to guide experimental work in fabricating ultra-low density films with precisely controlled properties.