Study of Synchrotron Radiation Near-Edge X-Ray Absorption Fine-Structure of Amorphous Hydrogenated Carbon Films at Various Thicknesses

Sarayut Tunmee,Tsuneo Suzuki,Satoru Arakawa,Kazuhiro Kanda,Hidetoshi Saitoh,Hideki Nakajima,Haruhiko Ito,Xiaolong Zhou,Keiji Komatsu,Ratchadaporn Supruangnet

doi:10.1155/2015/276790

Abstract

The compositions and bonding states of the amorphous hydrogenated carbon films at various thicknesses were evaluated via near-edge X-ray absorption fine-structure (NEXAFS) and elastic recoil detection analysis combined with Rutherford backscattering spectrometry. The absolute carbonsp2contents were determined to decrease to 65% from 73%, while the hydrogen contents increase from 26 to 33 at.% as the film thickness increases. In addition, as the film thickness increases, theπ⁎(C=C),σ⁎(C–H),σ⁎(C=C), andσ⁎(C≡C) bonding states were found to increase, whereas theπ⁎(C≡C) andσ⁎(C–C) bonding states were observed to decrease in the NEXAFS spectra. Consequently, the film thickness is a key factor to evaluate the composition and bonding state of the films.

Highlights

Amorphous hydrogenated carbon (a-C:H) films have attracted considerable attention in recent years for many reasons, such as excellent corrosion resistance, high hardness, high wear resistance, and good biocompatibility [1, 2]
Previous works [4, 6,7,8] have reported that both near-edge X-ray absorption fine-structure (NEXAFS) and photoelectron spectroscopy (PES) can successfully extract the chemical structures of diamond-like carbon (DLC) films
The aim of this study is to investigate the chemical characteristics of films, the compositions and bonding states at various thicknesses using NEXAFS spectroscopy at the 3.2a beamline at the synchrotron facility in Thailand

Summary

Introduction

Amorphous hydrogenated carbon (a-C:H) films have attracted considerable attention in recent years for many reasons, such as excellent corrosion resistance, high hardness, high wear resistance, and good biocompatibility [1, 2]. These films have the potential for many applications, for example, magnetic storage disks, automotive industry, biomedical parts, and solar cells [1,2,3]. Previous works [4, 6,7,8] have reported that both NEXAFS and PES can successfully extract the chemical structures of diamond-like carbon (DLC) films. The SR source is one of the best sources for characterizing the local structures of films

Objectives

Results

Conclusion