Thermal modulation of optical and electronic features of 2D Molybdenum Disulfide on SiO2/Si

Abstract

Two-dimensional materials like molybdenum disulfide (MoS₂) are promising for future electronic and optoelectronic devices. Single-layer MoS₂ (1L-MoS₂), with its 1.8 eV bandgap and strong fluorescence, is a key candidate, but achieving uniform large-scale synthesis remains difficult. Properties such as strain and doping are strongly influenced by both the growth method and the substrate. This study compares 1L-MoS₂ grown by chemical vapor deposition on SiO₂/Si with samples from gold-assisted exfoliation, applying thermal treatments in O₂ and Ar to tune physical properties. Raman and photoluminescence analyses show that Ar mainly reduces strain, while O₂ also decreases n-type doping and enhances fluorescence up to sevenfold. No significant morphological damage occurs below 225 °C. These results suggest a reproducible post-synthesis strategy to optimize MoS₂ for device applications, regardless of the growth method. This work was funded by the Italian MUR PNRR project SAMOTHRACE (ECS00000022) and by the European Union Next Generation EU, Mission 4 Component 1 CUP B53D23004460006 (Finanziato dall’Unione europea-Next Generation EU, Missione 4 Componente 1 CUP B53D23004460006).