Layer-Controlled Continuous MoS2 Growth using Spin-Coatable Metal Precursor Buffer

Abstract

Continuous large-area MoS₂ growth holds significant potential for next-generation optoelectronic applications, yet achieving it efficiently and reproducibly with conventional chemical vapor deposition (CVD) process remains a challenge due to inconsistent precursor adsorption and non-uniform nucleation. In this study, we developed a pH-optimized metal precursor buffer that enables uniform spin-coating and facilitates continuous MoS₂ growth. Sodium cholate (SC) acts as both a dispersant and a buffer, transforming molybdenum oxide into a dispersion-stable sodium molybdate (Na₂MoO₄)/SC complex. This complex forms a stable, uniformly spin-coatable dispersion at pH = 5.3, allowing it to establish hydrogen bonds with the SiO₂/Si substrate. Additionally, increasing the complex concentration enhances precursor adsorption, enabling controlled MoS₂ layer formation via CVD. Using this approach, we successfully fabricated continuous, centimeter-scale MoS₂ films in varying layer numbers. Real-time observation reveals the growth kinetics of continuous MoS₂ film in terms of contrast value, according to reaction time and temperature, indicating that the growth can occur at temperatures as low as 500 ºC. This stable, scalable, and reproducible spin-coating technique, utilizing a metal precursor buffer, offers a robust pathway for large-area transition metal chalcogenide structures, advancing the development of 2D material-based applications.