Ultrathin Oxide Films by Atomic Layer Deposition on Graphene

TL;DR

This paper demonstrates a method to create ultrathin, mechanically robust, and impermeable oxide films on graphene using Atomic Layer Deposition, with potential applications in coatings, membranes, and flexible electronics.

Contribution

It introduces a novel process for fabricating ultrathin oxide films with controlled thickness and high mechanical integrity on graphene substrates.

Findings

Ultrathin alumina films have a Young's modulus of 154 GPa.

Films are impermeable to gases, indicating pinhole-free coverage.

The method produces mechanically robust, free-standing oxide membranes.

Abstract

In this paper, a method is presented to create and characterize mechanically robust, free standing, ultrathin, oxide films with controlled, nanometer-scale thickness using Atomic Layer Deposition (ALD) on graphene. Aluminum oxide films were deposited onto suspended graphene membranes using ALD. Subsequent etching of the graphene left pure aluminum oxide films only a few atoms in thickness. A pressurized blister test was used to determine that these ultrathin films have a Young's modulus of 154 \pm 13 GPa. This Young's modulus is comparable to much thicker alumina ALD films. This behavior indicates that these ultrathin two-dimensional films have excellent mechanical integrity. The films are also impermeable to standard gases suggesting they are pinhole-free. These continuous ultrathin films are expected to enable new applications in fields such as thin film coatings, membranes and flexible electronics.