Chemical Structural Analysis of Diamondlike Carbon Films with Different Electrical Resistivities by X-ray Photoelectron Spectroscopy

Abstract

The chemical structure of diamondlike carbon (DLC) has been clarified by means of the quantitative analysis of the C 1s X-ray photoelectron spectra of the DLC films with different electrical resistivities prepared by the unbalanced magnetron sputtering (UBMS) method. The observed C 1s spectra showed asymmetric shapes and shifts of peak positions depending on the electrical resistivity of the films. Every spectrum was decomposed into four chemical components that were represented by the Doniach–Šunjić (DŠ) function convoluted with a Gaussian function. The structures corresponding to the chemical components were analyzed by considering that the electrical resistivity of DLC increases as the amount of hydrogen increases. The assignments of the chemical components are as follows: in order of binding energy, sp3 carbon with carbon–carbon bonds (C–C sp3 carbon, 283.7–283.8 eV), sp2 carbon with carbon–carbon bonds (C–C sp2 carbon, 284.2–284.3 eV), sp2 carbon with hydrogen–carbon bonds (H–C sp2 carbon, 284.7–284.8 eV), and sp3 carbon with hydrogen–carbon bonds (H–C sp3 carbon, 285.3–285.4 eV).