Two-dimensional Ga$_2$O$_3$ glass: a large scale passivation and protection material for monolayer WS$_2$

TL;DR

This paper introduces a large-scale, ultrathin Ga$_2$O$_3$ glass coating that passivates and protects monolayer WS$_2$, outperforming hBN in scalability and optical enhancement for optoelectronic applications.

Contribution

The study demonstrates that Ga$_2$O$_3$ glass is an effective, scalable alternative to hBN for large-scale passivation and optical enhancement of monolayer TMDCs.

Findings

Ga$_2$O$_3$ glass enhances optical performance of WS$_2$ monolayers.

Ga$_2$O$_3$ outperforms hBN in scalability and protection.

Ga$_2$O$_3$ is suitable for large-scale heterostructure fabrication.

Abstract

Atomically thin transition metal dichalcogenide crystals (TMDCs) have extraordinary optical properties that make them attractive for future optoelectronic applications. Integration of TMDCs into practical all-dielectric heterostructures hinges on the ability to passivate and protect them against necessary fabrication steps on large scales. Despite its limited scalability, encapsulation of TMDCs in hexagonal boron nitride (hBN) currently has no viable alternative for achieving high performance of the final device. Here, we show that the novel, ultrathin Ga$_2$O$_3$ glass is an ideal centimeter-scale coating material that enhances optical performance of the monolayers and protects them against further material deposition. In particular, Ga$_2$O$_3$ capping of commercial grade WS$_2$ monolayers outperforms hBN in both scalability and optical performance at room temperature. These properties make Ga$_2$O$_3$ highly suitable for large scale passivation and protection of monolayer TMDCs in functional heterostructures.