A study of laser-ion-deposited carbon films on tungsten by x-ray diffraction, field ion microscopy, and electron spectroscopy

Abstract

Thin carbon films have been deposited on polycrystalline tungsten foil as well as field ion microscope (FIM) tips by laser-ion deposition in a high-vacuum environment with an ion extraction voltage of -2 kV. Structural characterization of these films has been carried out by using low-angle x-ray diffraction (XRD) and FIM. The low-angle XRD reveals the formation of an interfacial α-W2C phase. The FIM image indicates the formation of the α-W2C phase on the tungsten tip. X-ray photoelectron spectroscopy has been utilized to reveal that the bonding character in the film is sp³. Further, x-ray-excited Auger electron spectroscopy has also supported the diamondlike nature of the films. The results are discussed, and a sequence of layers deposited on tungsten is suggested in view of the structural match.