Monolayer molybdenum disulfide is considered an extremely promising two-dimensional material for innovative electronics due to its direct bandgap and high charge-carrier mobility. The optical and electronic properties of monolayer MoS₂ can, however, be strongly influenced by the specific synthesis route, posing challenges for industrial-scale production. In this study, we investigated the effects of moderate temperature thermal treatments under a controlled O₂ atmosphere on the properties of monolayer MoS₂ flakes. We found that the treatments can effectively tune the doping level of monolayer MoS₂. Notably, 225 °C was identified as the optimal temperature for enhancing its optical emission properties. Our findings suggest that the removal of sulfur vacancies and impurities underlies these effects, demonstrating a promising approach for tuning the properties of monolayer MoS₂ at mild temperatures.

Interface and bulk defects are detrimental for the performance of 4H-Silicon Carbide (4H-SiC) electronic devices and thermal annealing is an essential procedure for the defects’ passivation and material optimization. In this study, we explore the impact on defectiveness of high-pressure (800 PSI ≈ 55 bar) thermal annealing in oxygen and helium atmospheres at 400 °C on 4H-SiC by examining exciton lifetimes. Three wafer types, representing different stages of device processing, were analyzed: (A) a bare epitaxial layer, (B) an oxide-coated sample, and (C) a sample that underwent post-oxide deposition annealing in nitric oxide (NO). Photoluminescence decay measurements after O₂ annealing show an increased exciton lifetime for the oxide-covered sample, a significant reduction for the bare epitaxial layer and no effects for NO post-deposition annealed sample. Comparisons with helium-annealed samples highlight the influence of oxygen in low-temperature annealing of SiC, presenting $$\:{\text{O}}_{2}$$ -based processing as a promising starting point for developing alternative post-deposition annealing methods.