Photoluminescence Enhancement of CVD-Grown MoS2 Monolayer by p-Type Doping Using Oxygen Annealing Technique

Two-dimensional (2D) films of MoS2 (MoS2-2D) were deposited on low-resistivity SiO2/Si substrates via the chemical vapor deposition (CVD) technique and subjected to p-doping with oxygen by annealing at different temperatures. Growth was carried out for different durations, i.e., 8 min, 15 min, and 20 min, by maintaining the growth temperatures of the two precursors (sulfur and MoO3) and pressure of the argon (Ar) carrier gas using a two-zone CVD reactor. Field-emission scanning electron microscopy (FESEM) analysis showed the presence of MoS2 grains with a triangular morphology distributed across the SiO2/Si substrate. The Raman spectroscopy study of the p-doped monolayer MoS2 showed a blueshift of the A1g peak indicative of oxygen doping. A stronger photoluminescence (PL) phenomenon was observed for the p-doped monolayer MoS2. The results show that the PL of MoS2-2D films can be enhanced in a simple and convenient way compatible with device fabrication processes by p-type doping and annealing in an oxygen atmosphere. This study highlights a facile method for enhancing the PL of MoS2 films through p-type doping with oxygen annealing, indicating the potential for improved optoelectronic device performance. X-ray photoelectron spectroscopy (XPS) analysis provides a detailed view of the chemical states within MoS2-2D films.