Influence of stress on the electron core level energies of noble gases implanted in hard amorphous carbon films

Abstract

In this work, we report the influence of the structural properties of the amorphous carbon matrix on the core-level electrons of implanted noble gases (Ar, Ne and Kr) used in the sputtering deposition process. The films were prepared in an ion beam-assisted deposition chamber (IBAD) including two Kauffman ion sources. Some fractional noble gas is trapped in the film during the assisted deposition and is subjected to the highly strained environment of the carbon matrix. X-Ray photoelectron spectroscopy shows that the noble-gas core-level energies shift linearly to lower binding energies with increasing compressive stress. It is suggested that these shifts are caused by compression of the outer valence wave-function of the implanted gas and by an extra-screening effect from valence electrons of the host atoms. The use of noble-gas core-level energy is proposed as a probe to determine the film stress.