Tailoring Dielectric Surface Charge via Atomic Layer Thickness

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• Solid-state nanopore surface properties critically influence single-particle dynamics.
• Tuning surface potential is key for optimizing nanopore-based sensing and separation.

Purpose of the Study:

• To demonstrate precise control over nanopore surface potential using atomically thin dielectric coatings.
• To investigate the impact of surface modification on particle capture and translocation dynamics.

Main Methods:

• Atomic layer deposition of alumina (Al2O3) on silicon nitride (Si3N4) micropores.
• Measurement of surface zeta-potential in aqueous buffer solutions.
• Analysis of capture rate and translocation speed of negatively charged polymeric particles.

Main Results:

• A 1 nm alumina coating significantly reduced surface zeta-potential, acting as a water-permeable layer.
• Zeta-potential was tunable with a resolution of 3.4 mV/nm by increasing dielectric thickness.
• Functionalized pores showed enhanced particle capture rates and translocation speeds due to reduced electroosmotic back flow.

Conclusions:

• Atomically thin dielectric coatings offer a versatile method for fine-tuning nanopore surface charge.
• This approach improves particle handling in nanopore devices.
• The technique is broadly applicable to various sensors and devices operating in aqueous environments.