Influence of charge transfer doping on the morphologies of C-60 islands on hydrogenated diamond C(100)-(2 x 1)

Nimmrich M, Kittelmann M, Rahe P, et al. Influence of charge transfer doping on the morphologies of C-60 islands on hydrogenated diamond C(100)-(2 x 1). Physical Review B. 2012;85(3): 35420.The adsorption and island formation of C-60 fullerenes on the hydrogenated C(100)-(2 x 1):H diamond surface is studied using high-resolution noncontact atomic force microscopy in ultrahigh vacuum. At room temperature, C-60 fullerene molecules assemble into monolayer islands, exhibiting a hexagonally close-packed internal structure. Dewetting is observed when raising the substrate temperature above approximately 505 K, resulting in two-layer high islands. In contrast to the monolayer islands, these double-layer islands form extended wetting layers. This peculiar behavior is explained by an increased molecule-substrate binding energy in the case of double-layer islands, which originates from charge transfer doping. Only upon further increasing the substrate temperature to approximately 615 K, the wetting layer desorbs, corresponding to a binding energy of the charge transfer-stabilized film of 1.7 eV