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We have studied the growth and the properties of (t)a-C:F films prepared by the deposition of mass separated 12C+ and 19F+ ions as a function of the F concentration. The films are always strongly F deficient due to the formation of volatile F2 and CFx molecules during the deposition process. A maximum F content of about 25 at. % is obtained for an ion charge ratio of C+:F+=1:1. The observed mechanical, optical, electrical, and structural properties as well as the thermal stability of the films are strongly influenced by the F content. A three step progression of the film structure is evident for increasing F concentration: the amorphous three-dimensional network of tetrahedrally bonded carbon atoms of pure carbon films (ta-C) with diamondlike properties is doped for very low F concentrations (ta-C:F). A further increase of the F content results first in transformation to a graphitelike amorphous structure (a-C:F) before the deposited films become porous and to a polymerlike one for the highest F content.

The feasibility of endohedral iron doping of C60 is studied using a mass selected ion beam to create an Fe+ beam with variable energy (60–380 eV, 1.2×10−3 C) which is directed at a C60 thin film. The surface is characterized by x-ray photoelectron spectroscopy, and oxidation of the samples is used to discriminate between Fe@C60 and carbides. The fullerene cages are damaged during the irradiation, and participate in direct Fe–C bond formation. The reaction with oxygen indicates the absence of sizable amount of Fe@C60. Comparison with reference samples composed of iron and damaged fullerene layers (by Ar+ irradiation) supports this interpretation. The experiment serves as a model study for the investigation of different metal-fullerene combinations.

Fe(65−x)Mo14C15B6Erx bulk metallic glasses have been investigated by means of photoelectron spectroscopy. In order to obtain a clean surface the samples were fractured and analyzed in vacuum. The impact of the incorporation of Er on the local atomic structure, the bonding, and the valence band density of states was examined. Our results show that Er addition modifies the B–C bonding environment, which is expressed in the appearance of an additional peak in the C 1s core level. It also affects the Fe 3s multiplet splitting, indicating changes in the valence band electronic configuration. The change in the electronic structure is corroborated by examination of x-ray photoelectron spectroscopy (XPS) valence band spectra.

Bulk metallic glasses consisting of Fe, Mo, Cr, C, B, and Er have been investigated by x-ray photoelectron spectroscopy, aimed to elucidate the local atomic structure of the amorphous phase. In order to examine the electronic properties of this class of material, photon energy dependent measurements in combination with argon-ion irradiation were employed to identify and separate surface and bulk contributions to the spectra. The core levels suggest the presence of a carbon-rich surface layer with oxidized boron and metals, and metal carbides and borides in the bulk. Exposure to molecular oxygen and annealing experiments probe the chemical reactivity of the material. Formation of boron oxides at comparably low temperatures (300°C) might have consequences for the stability of the amorphous phase. We observe variations in binding energy of the Fe 3p core level with respect to the alloy composition, which indicate changes in the chemical state of iron.