Chemical inertness of planar silicene – The case of oxygen exposure

• Oxygen exposition of planar silicene heterostructure was investigated using LEEM and ARPES. • Silicene’s diffraction pattern was still present after 1200 L dose of O 2 . • Linear dispersion bands resisted 8000 L does of O 2 . • Air exposition was attempted, which resulted in irreversible destruction of silicene heterostructure. • Careful water exposure was conducted, revealing silicene heterostructure decomposition at 600 L. The oxidation behavior of planar silicene heterostructures grown on Si(1 1 0) heterostructure is investigated through angle-resolved photoemission spectroscopy (ARPES) and low-energy electron microscopy (LEEM). Remarkably, even after exposure to more than 1000 L of oxygen material continues to exhibit hallmark silicene features – linear dispersion near the Γ-point in ARPES and characteristic surface morphology in LEEM. Such resilience contradicts assumptions of silicene’s oxidative degradation and indicates a kinetically hindered or self-limited oxidation process. This enhanced stability can originate from interfacial effects unique to the Au/Si(1 1 0) substrate, which could modify or even self-passivate the silicene heterostructure, inhibiting formation of continuous oxide layer. These findings provide new mechanistic insight into the oxidation kinetics within two-dimensional systems and highlight the critical role of substrate-film interactions to determine environmental durability.