Photoelectron emission and Raman scattering studies of nitrogenated tetrahedral amorphous carbon films

J. R. Shi, J. P. Wang, A. T.S. Wee, C. B. Yeo, C. T. Cheng, M. Ueda, S. Tomioka, J. Ohsako

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14 Scopus citations

Abstract

Nitrogenated tetrahedral amorphous carbon (N:ta-C) films prepared by the filtered cathodic vacuum arc technique were studied by x-ray photoelectron spectroscopy (XPS), Raman spectroscopy, spectroscopic ellipsometry, ultraviolet photoelectron spectroscopy and temperature dependent resistance measurement. As the nitrogen flow rate varies from 0 to 20 sccm, the nitrogen content in the deposited film increases from 0 to 4.6 at.%. Curve fitting of the C 1s and N 1s XPS spectra shows that the C-C sp 3 fraction decreases with an increase in nitrogen content and that the nitrogen atoms are mainly bonded in sp 2 C-N bonds. The pure ta-C film has a work function of 4.35 eV and the N:ta-C films have a value around 4.55 eV. With an increase in nitrogen flow rate, the intensity ratio of the D peak to the G peak, I D/I G increases monotonously from 0.44 to 1.25 and the G peak width decreases from 220 to 199 cm -1. The Tauc optical band gap decreases from 2.2 to 1.8 eV.

Original languageEnglish (US)
Pages (from-to)5966-5970
Number of pages5
JournalJournal of Applied Physics
Volume92
Issue number10
DOIs
StatePublished - Nov 15 2002

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Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.

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