  Quasi free-standing monolayer graphene can be produced by intercalating
species like oxygen or hydrogen between epitaxial graphene and the substrate
crystal. If the graphene is indeed decoupled from the substrate, one would
expect the observation of a similar electronic dispersion and many-body
effects, irrespective of the substrate and the material used to achieve the
decoupling. Here we investigate the electron-phonon coupling in two different
types of quasi free-standing monolayer graphene: decoupled from SiC via
hydrogen intercalation and decoupled from Ir via oxygen intercalation. Both
systems show a similar overall behaviour of the self-energy and a weak
renormalization of the bands near the Fermi energy. The electron-phonon
coupling is found to be sufficiently weak to make the precise determination of
the coupling constant lambda through renormalization difficult. The estimated
value of lambda is 0.05(3) for both systems.
