Gated MoS2/SiN Nanochannel for Tunable Ion Transport and Protein Translocation

TL;DR

This paper presents a novel MoS2/SiN hybrid nanochannel that can be electrically tuned for ion transport, energy harvesting, and single-molecule detection, demonstrating versatile control over nanofluidic processes.

Contribution

It introduces a new fabrication method for ultra-thin MoS2/SiN nanochannels enabling electrical control of ion transport and demonstrates their application in energy harvesting and biomolecule sensing.

Findings

Gate voltage modulates ionic conductance and selectivity.

Nanochannels can harvest osmotic energy from salt gradients.

Single BSA molecules produce long translocation signals.

Abstract

Ionic transport in nanofluidic channels holds great promise for applications such as single-molecule analysis, molecular manipulation, and energy harvesting. However, achieving precise control over ion transport remains a major challenge. In this work, we introduce a MoS2 SiN hybrid nanochannel architecture that enables electrical tuning of ionic transport via external gating, and we examine its potential for osmotic power generation and single molecule detection. To fabricate the channels, we employed a combined focused ion beam (FIB) milling and dry transfer method, producing sub 10 nm thick structures while preserving the structural integrity and electronic properties of MoS2, essential for reliable surface charge modulation. We first investigated how the gate voltage influences ionic conductance, finding evidence of gate dependent modulation of ion selectivity under different bias polarities. Next, by applying a salt concentration gradient across the nanochannels, we demonstrated the feasibility of this platform for osmotic energy harvesting. Finally, we tested the system for single molecule sensing, showing that linearized bovine serum albumin (BSA) produced translocation signals with notably long dwell times. Together, these results highlight gated MoS2 SiN nanochannels as a promising platform for tunable nanofluidics, with potential applications in controlled molecular transport and energy harvesting from osmotic gradients.