Edge conductivity in PtSe$_2$ nanostructures

TL;DR

This study models and analyzes the edge conductivity in nanoscale PtSe$_2$ structures, revealing that electrical transport may be dominated by edge states in small nanoflakes, which is crucial for nanoelectronic applications.

Contribution

The paper introduces a deep neural network-based interatomic potential for PtSe$_2$ and demonstrates edge-localized conductivity in nanostructures below 10 nm.

Findings

Edge stability depends on termination type.

Electrical conductivity is localized on edges for <10 nm.

Transport channels may be edge-dominated in thin films.

Abstract

PtSe$_2$ is a promising 2D material for nanoelectromechanical sensing and photodetection in the infrared regime. One of its most compelling features is the facile synthesis at temperatures below 500 {\deg}C, which is compatible with current back-end-of-line semiconductor processing. However, this process generates polycrystalline thin films with nanoflake-like domains of 5 to 100 nm size. To investigate the lateral quantum confinement effect in this size regime, we train a deep neural network to obtain an interatomic potential at DFT accuracy and use that to model ribbons, surfaces, nanoflakes, and nanoplatelets of PtSe$_2$ with lateral widths between 5 to 15 nm. We determine which edge terminations are the most stable and find evidence that the electrical conductivity is localized on the edges for lateral sizes below 10 nm. This suggests that the transport channels in thin films of PtSe$_2$ might be dominated by networks of edges, instead of transport through the layers themselves.