Abstract
Many energy conversion and storage devices exploit structured ceramics with large interfacial surface areas. Vertically aligned carbon nanotube (VACNT) arrays have emerged as possible scaffolds to support large surface area ceramic layers. However, obtaining conformal and uniform coatings of ceramics on structures with high aspect ratio morphologies is non-trivial, even with atomic layer deposition (ALD). Here we implement a diffusion model to investigate the effect of the ALD parameters on coating kinetics and use it to develop a guideline for achieving conformal and uniform thickness coatings throughout the depth of ultra-high aspect ratio structures. We validate the model predictions with experimental data from ALD coatings of VACNT arrays. However, the approach can be applied to predict film conformality as a function of depth for any porous topology, including nanopores and nanowire arrays.
Highlights
Recent advances in the synthesis and processing of carbon nanotubes (CNTs) have enabled the prospect of their integration into existing technologies that exploit the high surface area of mesoporous ceramic films [1]
The large surface area of the highaspect-ratio structure requires a large number of precursor molecules such that the location and rate of adsorption is critical to the coating kinetics
To understand how Atomic layer deposition (ALD) process parameters influence the coatings of high aspect ratio structures, we develop a model based on a continuum diffusion approach that takes into account adsorption of precursor molecules
Summary
Recent advances in the synthesis and processing of carbon nanotubes (CNTs) have enabled the prospect of their integration into existing technologies that exploit the high surface area of mesoporous ceramic films [1]. The thickness of the coating deep inside the CNT array increases with the exposure time, as the precursor molecules have more time to diffuse down to available adsorption sites.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have