Annealing Response of Monolayer MoS₂ Grown by Chemical Vapor Deposition

Abstract

Thermal stability of 2D materials under different conditions must be carefully examined since they can be submitted to heat during device fabrication and/or during application. In this work, the thermal stability of monolayer molybdenum disulfide (MoS2) under vacuum (∼10−7 mbar) annealing was investigated. While MoS2 bulk is stable up to 1050°C, monolayer MoS2 was only stable up to 700°C. At 800°C, significant degradation occurred, while at 900°C, all MoS2 was converted to MoO3 and MoO2. Results indicate that sulfur was lost during high temperature annealing, while no significant molybdenum loss was detected (no MoO3 evaporation occurred). Base pressure during annealing had a strong influence in the thermal degradation, since MoS2 was stable at 800°C when pressure was reduced to ∼10−9 mbar, while MoS2 was completely converted to MoO3 and MoO2 under 220 mbar of dry argon at 500°C, possibly due to the presence of oxidation agents. Results highlight the importance of the careful choice of conditions during growth and application of MoS2.

Growth of two-dimensional Janus MoSSe by a single in situ process without initial or follow-up treatments

“…This result further suggests that there is a critical minimum thickness for the successful growth of Janus MoSSe using our approach. Similar behaviors were reported in previous publications 33,34 . In these reports, the mono-layer MoS 2 was cracked when annealed above a critical temperature (this temperature depends on the approach).…”

Unleashing the Power of 2D MoS2: In Situ TEM Study of Its Potential as Diffusion Barriers in Ru Interconnects

“…Consequently, interdiffusion occurs when the samples are subjected to temperatures exceeding 800 °C, regardless of whether the MoS 2 is a multilayer (ML) or monolayer (1L), underscoring the inherent blocking capability of MoS 2 against interdiffusion, independent of its thickness. The literature demonstrated that MoS 2 starts to vanish when the temperature is higher than 700 °C; , the findings about the thermal stability in the present study are consistent. Drawing from the temperature range employed in the present investigation, it is speculated that the breaking of covalent bonds initiates at 750 °C, while MoS 2 retains the ability to impede Si diffusion.…”

“…Si atoms are the dominant species involved in the diffusion process . As ML-MoS 2 is damaged at high temperatures, a significant quantity of Si atoms diffuses through ML-MoS 2 with higher diffusivity and reacts with the Ru film to form Ru 2 Si 3 .…”

Direct visualization of out-of-equilibrium structural transformations in atomically thin chalcogenides

“…Furthermore, if the sulfur content is reduced to below 60 atomic percent, a mixture of Mo and Mo 2S3 forms. It has been established in the literature that sulfur vacancies, having a low formation energy, are the dominant defect species in few-layer MoS2 [28], and that annealing in the 500 ˚C < T < 1000 ˚C range can lead to loss of sulfur atoms on a time scale of just 30 minutes [29]. Moreover, the general phenomena of melting point depression in quantum-confined materials relative to their bulk counterparts is well known [30,31].…”