A Semi-Grand Canonical Kinetic Monte Carlo study of Single-Walled Carbon Nanotubes growth

TL;DR

This paper develops a kinetic Monte Carlo model to predict how different chiralities of single-walled carbon nanotubes grow, revealing how synthesis conditions influence their selectivity and growth rates.

Contribution

It introduces a simple, efficient model for predicting nanotube growth rates based on interface energies and synthesis parameters, advancing understanding of chiral selectivity.

Findings

Growth rate distribution varies non-monotonically with interface energies.

Certain synthesis conditions favor high selectivity for specific chiral angles.

The model uncovers the interplay between external conditions and interface energetics.

Abstract

Single-walled carbon nanotubes exist in a variety of different geometries, so-called chiralities, that define their electronic properties. Chiral selectivity has been reported in catalytic chemical vapor deposition synthesis experiments, but the underlying mechanisms remain poorly understood. In this contribution, we establish a simple model for the prediction of the growth rates of carbon nanotubes of different chiralities, as a function of energies characterizing the carbon nanotube-catalyst interface and of parameters of the synthesis. The model is sampled efficiently using kinetic Monte Carlo simulations in the semi-grand canonical ensemble, uncovering the interplay of the external experimental conditions and the configuration and energetics of the interface with the catalyst. In particular, the distribution of chiral angle dependent growth rates follows non-monotonic trends as a function of interface energies. We analyze this behavior and use it to identify conditions that lead to high selectivity for a variety of chiral angles.