High-quality, large-grain MoS2 films grown on 100 mm sapphire substrates using a novel molybdenum precursor

TL;DR

This paper demonstrates a scalable chemical vapor deposition method to produce large-area, high-quality monolayer MoS2 films on 100 mm sapphire wafers using a novel molybdenum precursor, advancing the potential for industrial applications.

Contribution

The study introduces a new molybdenum precursor mixture for CVD growth of MoS2, achieving large, high-quality monolayer films suitable for scalable production.

Findings

Large grains of 1-75 microns achieved

Monolayer MoS2 films identified under specific growth conditions

Post-growth annealing improves film quality and composition

Abstract

Two-dimensional MoS2 is a crystalline semiconductor with high potential for numerous technologies. Research in recent years has sought to exploit the direct band gap and high carrier mobility properties of monolayer MoS2 for functional applications. To date, the production of MoS2 has remained at the research level and samples are usually synthesized in small quantities using small yield, expensive techniques. In order to realize scalable MoS2-based technology, large-area, high-quality and affordable MoS2 wafers must become available. Here we report on MoS2 films grown on 100 mm sapphire wafers by a chemical vapor deposition process utilizing hydrogen sulfide and molybdenum precursor mixtures consisting of Na2MoO4 and NaCl. The grains of these films are faceted, large-area, on the order of 1-75 microns in length on edge. Growth conditions are identified that yield monolayer MoS2 films. Raman spectroscopy shows an E2g and A1g peak separation of 17.9-19.1 cm-1. Photoluminescence spectroscopy shows that annealing the films post-growth suppresses trion emission. X-ray photoelectron spectroscopy of the annealed films shows an in increase in the S:Mo concentration ratio from 1.90:1.00 to 2.09:1.00.