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Optical Properties of Diamond-Like Carbon Films Deposited by Laser Ablation

Published online by Cambridge University Press:  10 February 2011

C. H. Seager ,
T. A. Friedmann  and
D. E. Bliss
C. H. Seager
Affiliation:
Sandia National Laboratories, Albuquerque, NM, 87185
T. A. Friedmann
Affiliation:
Sandia National Laboratories, Albuquerque, NM, 87185
D. E. Bliss
Affiliation:
Sandia National Laboratories, Albuquerque, NM, 87185
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Abstract

Various optical techniques, including Photothermal Deflection Spectroscopy (PDS), ellipsometry, and transmission measurements, have been used to examine the optical properties of diamond like C films deposited at various laser power densities on Si and fused quartz. The absorption coefficients of these films are typically above 5 × 104 cm−1 throughout the visible part of the spectrum, decreasing quasi-exponentially in the infra-red. Larger sp2/sp3 bonding ratios caused by deposition at lower laser power settings noticeably increase film absorption coefficients. While Tauc plots of our absorption data yield bandgaps of 1.5-1.0 eV, the quality of these fits is unimpressive and the slopes are unphysically low. Rather than modelling these materials as narrow gap semiconductors, we have pursued another avenue: treating the films as a mixture of small graphitic particles embedded in a diamond, sp3-like matrix. We will discuss the results of this approach as well as the evolution of the optical properties after thermal anneals.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 416: Symposium DD – Diamond for Electronic Applications , 1995 , 145
Copyright
Copyright © Materials Research Society 1996

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References

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