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Operando Study of Thermal Oxidation of Monolayer MoS2



Sangwook Park, Angel Garcia-Esparza, Hadi Abroshan, Baxter Abraham, John Vinson, Allesandro Gallo, Dennis Nordlund, Joonsuk Park, Taeho R. Kim, Roberto Alonso-Mori, Dimosthenis Sokaras, Xiaolin Zheng


Monolayer MoS2 is a promising semiconductor to overcome the physical dimension limits of the microelectronic devices. Understanding the thermochemical stability of MoS2 is essential since these devices generate heat and are susceptible to oxidative environments. Herein, we show the promoting effect of molybdenum oxides (MoOx) particles on the thermal oxidation of MoS2 monolayers employing operando XAS, ex-situ SEM, and XPS. We demonstrate that CVD-grown MoS2 monolayers contain intrinsic MoOx and are quickly oxidized at 100 °C (3 vol % O2/He), in contrast to previously reported oxidation thresholds (e.g., 250 °C, t ≤ 1 h in the air). Otherwise, removing MoOx increases the thermal oxidation onset temperature of monolayer MoS2 to 300 °C. These results indicate that MoOx promote oxidation. An oxide-free lattice is critical to the long-term stability of monolayer MoS2 in state-of-the-art two-dimensional electronic, optical, and catalytic applications.
Advanced Science


Park, S. , Garcia-Esparza, A. , Abroshan, H. , Abraham, B. , Vinson, J. , Gallo, A. , Nordlund, D. , Park, J. , Kim, T. , Alonso-Mori, R. , Sokaras, D. and Zheng, X. (2021), Operando Study of Thermal Oxidation of Monolayer MoS2, Advanced Science, [online],, (Accessed April 15, 2024)
Created March 1, 2021, Updated October 12, 2021