Phenomenological Growth Regimes in Liquid-Precursor CVD of MoS${}_2$ on Functional Substrates

Abstract

The integration of two-dimensional transition-metal dichalcogenides (TMDCs) onto functional substrates remains constrained by stochastic vapor-phase growth dynamics. Here, we show that liquid-phase precursor chemical vapor deposition (CVD) of MoS${}_2$ introduces growth conditions that are consistent with a substrate-influenced reaction-diffusion process. By utilizing pre-growth spin-coated MoO${}_3$ intermediates across a diverse crystalline library (sapphire, SrTiO${}_3$, rutile TiO${}_2$, MgO, and 6H-SiC), we find that substrate-dependent variations in precursor wetting, surface chemistry, and inferred mass-transport constraints correlate with distinct growth morphologies. These substrate-dependent growth regimes are interpreted in terms of reduced effective lateral growth length on SrTiO${}_3$, possible precursor anchoring on TiO${}_2$, likely chemical surface restructuring on MgO, and possible step-edge growth on SiC. Raman and photoluminescence spectroscopy reveal substrate-dependent variations in vibrational and optical response that correlate with differences in strain, charge environment, and dielectric screening. Ultimately, this work highlights a substrate-dependent reaction-diffusion framework as a potentially useful route for tuning the structural and optical properties of large-area 2D materials.

9 pages, 3 figures