Near-Edge X-ray Absorption Fine-Structure, X-ray Photoemission, and Fourier Transform Infrared Spectroscopies of Ultrananocrystalline Diamond/Hydrogenated Amorphous Carbon Composite Films

Abstract

The chemical bonding structure of ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon (a-C:H) composite films prepared by pulsed laser deposition was examined by near-edge X-ray absorption fine-structure (NEXAFS), X-ray photoemission, and Fourier transform infrared (FTIR) spectroscopies. An intense sp3-CH peak was observed in the FTIR spectrum. This implies that the sp3-CH peak originates from the grain boundaries between UNCD crystallites, wherein dangling bonds are terminated with hydrogen atoms. The presence of an intense σ*C–C peak in the NEXAFS spectrum and a narrow sp3 peak in the photoemission spectrum was specific to UNCD/a-C:H films; these confirm the existence of UNCD crystallites.