Non-invasive digital etching of van der Waals semiconductors

TL;DR

This paper introduces a non-invasive, atomically precise etching method for van der Waals semiconductors using selective alloying and wet etching, enabling high-quality material manipulation for quantum and microelectronic applications.

Contribution

It presents a novel protocol for non-invasive, atomic-scale digital etching of van der Waals materials via low-temperature alloying and wet etching, with detailed mechanism analysis.

Findings

High charge mobility in etched MoS₂ comparable to pristine material

Selective alloying enables atomic-level precision in etching

The method is non-invasive and preserves material quality

Abstract

The capability to finely tailor material thickness with simultaneous atomic precision and non-invasivity would be useful for constructing quantum platforms and post-Moore microelectronics. However, it remains challenging to attain synchronized controls over tailoring selectivity and precision. Here we report a protocol that allows for non-invasive and atomically digital etching of van der Waals transition-metal dichalcogenides through selective alloying via low-temperature thermal diffusion and subsequent wet etching. The mechanism of selective alloying between sacrifice metal atoms and defective or pristine dichalcogenides is analyzed with high-resolution scanning transmission electron microscopy. Also, the non-invasive nature and atomic level precision of our etching technique are corroborated by consistent spectral, crystallographic and electrical characterization measurements. The low-temperature charge mobility of as-etched MoS$_2$ reaches up to $1200\,$cm$^{2}\cdot$V$^{-1}\cdot$s$^{-1}$, comparable to that of exfoliated pristine counterparts. The entire protocol represents a highly precise and non-invasive tailoring route for material manipulation.