Core level shift of diamond and graphite upon Ar+ ion bombardment

Abstract

Diamond-like films (DLF) and highly oriented pyrolytic graphite (HOPG) are made of two allotropes of carbon, diamond and graphite. Each of Bulk DFL and Bulk HOPG which is untreated has a XPS spectra corresponding to some coordination numbers (CN). After the Ar+ bombardment, atomic hole defect, including single atomic hole and multi-atomic hole, occurs for both of DFL and HOPG. Atomic hole defect will cause core level shift due to the quantum trapping effect and polarization. This leads to the change of CN of some atoms of DFL and HOPG samples. As a result, the XPS spectra will change. With different doses of Ar+ ions, different XPS spectra’s are obtained. Difference spectra and peak fitting are used for the analysis of XPS spectra. The software Getdata is used to digitalize figures and explore data from figures. Other than that, the software Origin is used to plot and analyze XPS spectra graphs. Based on the data obtained from the experiment, Bond order-length-strength (BOLS) theory is used to calculate the binding energy of C1s electron with different CN’s, which are useful for further investigation in this field such as the layer- resolved Raman shift.