Intercalated samarium as an agent enabling the intercalation of oxygen under a monolayer graphene film on iridium

Using thermal desorption time-of-flight mass spectrometry and thermionic methods, it is shown that oxygen does not intercalate under a graphene monolayer grown correctly on iridium, at least at temperatures of $T$ = 300–400 K and exposures below 12000 L. However, if the graphene film on iridium is preliminary intercalated with samarium atoms (up to coverage of $\theta_{\mathrm{Sm}}$ = 0.2–0.45), the penetration of oxygen atoms under the graphene film is observed. The oxygen atoms in the intercalated state are chemically bonded to samarium atoms and remain under graphene up to high temperatures ($\sim$2150 K).