Boron Nitride Nanoporous Membranes with High Surface Charge by Atomic Layer Deposition

Abstract

In this work, we report the design and the fine-tuning of boron nitride single nanopore and nanoporous membranes by atomic layer deposition (ALD). First, we developed an ALD process based on the use of BBr and NH as precursors in order to synthesize BN thin films. The deposited films were characterized in terms of thickness, composition, and microstructure. Next, we used the newly developed process to grow BN films on anodic aluminum oxide nanoporous templates, demonstrating the conformality benefit of BN prepared by ALD, and its scalability for the manufacturing of membranes. For the first time, the ALD process was then used to tune the diameter of fabricated single transmembrane nanopores by adjusting the BN thickness and to enable studies of the fundamental aspects of ionic transport on a single nanopore. At pH = 7, we estimated a surface charge density of 0.16 C·m without slip and 0.07 C·m considering a reasonable slip length of 3 nm. Molecular dynamics simulations performed with experimental conditions confirmed the conductivities and the sign of surface charges measured. The high ion transport results obtained and the ability to fine-tune nanoporous membranes by such a scalable method pave the way toward applications such as ionic separation, energy harvesting, and ultrafiltration devices.

Tunable Anion-Selective Transport through Monolayer Graphene and Hexagonal Boron Nitride

“…Electrostatic charging of the surfaces of 2D materials on water has been demonstrated, with estimates for graphene on water 13 as −0.6 and −0.16 C/m 2 for hBN. 27 Such extrinsic charging on Figure 1. Experimental setup and ion-selectivity schematic for the transport of ions through a charged membrane driven by a salinity gradient alone.…”

Surface coatings for solid-state nanopores

“…264 Alternatively, electron beaminduced deposition (EBID) is a technique for spatially localized deposition that involves physisorption of precursor molecules on the surface followed by deposition mediated by electrons. 265,266 Potential benefits of depositions on membranes containing a nanopore, besides the obvious change in pore size and shape, 140,142,143,146,147,150,151,154 include reduction of recording noise, 142,149 modification of surface properties such as charge or hydrophobicity, 130,140,142,147,148 control of current rectification, 152 and manipulation of surface interactions with analytes of interest or with other molecules in a sample. 141 While depositions of coatings from the gas phase make it possible to reduce the pore diameter, the same process leads to a concomitant, and often undesired increase in nanopore length.…”

Recent Progress on Titanium Dioxide Nanomaterials for Photocatalytic Applications

“…[128] Atomic layer deposition (ALD) is gaining increasinga ttention in the energya nd environmental fields as ap romising methodf or surfacem odification and protection. [132][133][134][135] The originality of ALD was given to Professor Aleskovskii and his team in 1960 when they realizedt he deposition of TiO 2 from TiCl 4 and H 2 O. [132][133][134][135] The originality of ALD was given to Professor Aleskovskii and his team in 1960 when they realizedt he deposition of TiO 2 from TiCl 4 and H 2 O.…”

“…[129][130][131] ALD is a vapor deposition method of ultrathin layers. [132][133][134][135] The originality of ALD was given to Professor Aleskovskii and his team in 1960 when they realizedt he deposition of TiO 2 from TiCl 4 and H 2 O. [136] ALD is ad eposition technique that derives from the CVD technique;i ti sb ased on two self-limiting reactions absolutely separated in the gas phases.…”