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Optical Properties of Carbon thin films Containing Nanoparticles

Published online by Cambridge University Press:  10 February 2011

M. Chhowalla ,
A. I. Munindradasa ,
K. G. Lim ,
G. A. J. Amaratunga  and
C. J. Kiely
M. Chhowalla
Affiliation:
Dept. of Electrical Eng. & Electronics, University of Liverpool, Brownlow Hill, Liverpool, L69 3GJ, UK
A. I. Munindradasa
Affiliation:
Dept. of Electrical Eng. & Electronics, University of Liverpool, Brownlow Hill, Liverpool, L69 3GJ, UK
K. G. Lim
Affiliation:
Dept. of Electrical Eng. & Electronics, University of Liverpool, Brownlow Hill, Liverpool, L69 3GJ, UK
G. A. J. Amaratunga
Affiliation:
Dept. of Electrical Eng. & Electronics, University of Liverpool, Brownlow Hill, Liverpool, L69 3GJ, UK
C. J. Kiely
Affiliation:
Dept. of Materials Science & Engineering, University of Liverpool, Brownlow Hill, Liverpool, L69 3GJ, UK
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Abstract

The incorporation of carbon nanoparticles in the forms of nanotubes and bucky onions have shown to improve the mechanical properties of amorphous carbon (a-C) thin films. In this paper we report on the change in the optical properties of a-C films containg nanoparticles. The optical band gap, index of refraction and extinction coefficient are studied. The optical band gap in highly tetrahedral amorphous carbon (ta-C) is found to be around 2 eV. It decreases almost linearly with the sp2 fraction. It is theorized that the clustering of the sp2 sites leads to a reduction in the band gap. In this paper, we study the influence of large sp2 clusters in forms of graphitic nanoparticles on the optical of ta-C. We find that the optical gap remains around 1.8 eV even with the large inclusions of clustered nanoparticles. Furthermore, the gap remains close to 1.8 eV even when the sp2 fraction in the amorphous matrix is increased. The index of refraction however is found to decrease with the sp2 fraction indicating a reduction in density.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 498: Symposium AA – Covalently Bonded Disordered Thin-Film Materials , 1997 , 115
Copyright
Copyright © Materials Research Society 1998

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References

REFERENCES

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