Exclusive Generation of Single-Atom Sulfur for Ultrahigh Quality Monolayer MoS$_2$ Growth

TL;DR

This paper introduces a novel method using single-atom sulfur derived from battery waste to grow ultrahigh-quality monolayer MoS₂ with minimal defects, advancing the production of high-performance 2D materials.

Contribution

The study demonstrates a new sulfur source, SPAN, for synthesizing high-quality monolayer MoS₂ with significantly reduced defects compared to traditional methods.

Findings

Ultralow defect density of ~7×10¹² cm⁻² in MoS₂

Narrowest PL emission peak with FWHM of ~47.11 meV at room temperature

Superior optical quality verified by resonance Raman and low-temperature PL

Abstract

Preparation of high-quality two-dimensional (2D) transition metal dichalcogenides (TMDCs) is the precondition for realizing their applications. However, the synthesized 2D TMDCs (e.g., MoS$_2$) crystals suffer from low quality due to the massive defects formed during the growth. Here, we report the single-atom sulfur (S1) as a highly reactive sulfur species to grow ultrahigh-quality monolayer MoS$_2$. Derived from battery waste, the sulfurized polyacrylonitrile (SPAN) is found to be exclusive and efficient in releasing S1. The monolayer MoS$_2$ prepared by SPAN exhibits an ultralow defect density of $~7\times 10^{12}$ cm$^{-2}$ and the narrowest photoluminescence (PL) emission peak with full-width at half-maximum of ~47.11 meV at room temperature. Moreover, the statistical resonance Raman and low-temperature PL results further verify the significantly lower defect density and higher optical quality of SPAN-grown MoS$_2$ than the conventional S-powder-grown samples. This work provides an effective approach for preparing ultrahigh-quality 2D single crystals, facilitating their industrial applications.