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Optical properties of diamond-like carbon thin films deposited by PECVD

Ismail, Bakar and Sarmid, Suriany and Deraman, Karim and Hussin, R. and Wan Shamsuri, Wan Nurulhuda and M. Yusof, M. Nor and Hamzah, Khaidzir and Ahmad, N. E. (2010) Optical properties of diamond-like carbon thin films deposited by PECVD. In: Regional Annual Fundamental Science Symposium 2010 (RAFSS 2010), 8-9 June 2010, Grand Seasons Hotel, Kuala Lumpur.

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Diamond-like carbon (DLC) thin films were deposited at different substrate temperatures using methane gas in DC-PECVD at 1x10-1 Torr. From the light transmission using UV-VIS spectroscopy it was found that the optical transition had changed from allowed indirect transition to forbidden direct transition as the substrate temperature increased. The photoluminescence study has shown that the recombination centre occurred at 1.738 eV. The observation in the present work shows that the Urbach energy decreases with increasing substrate temperature provides evidence that such films have a narrowed band tail. This decrease in Urbach energy is due to a more ordered structure with lower hydrogen concentration and larger cluster by the increase in the degree of cross-linking of the C-C network. Distorted cluster which contribute to the broadening of the band tail may also contribute to the PL peak width. As the substrate temperature increases, the cluster size in the tetrahedral hydrogenated amorphous carbon (ta-C:H) increases, resulting in smaller band gap and the structure is more ordered as the decrease in Urbach energy, give the decrease in PL peak energy.

Item Type:Conference or Workshop Item (Paper)
Uncontrolled Keywords:diamond like carbon, DC-PECVD, optical properties, photoluminescence, amorphous carbon
Subjects:Q Science
ID Code:24146
Deposited By: Mrs Liza Porijo
Deposited On:25 Jun 2012 01:40
Last Modified:25 Jun 2012 01:44

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