Open AccessOptical properties of Diamond like Carbon films prepared by DC-PECVD
Author(s) -
Sonam Tshomo,
Ali Kamel Mohsin,
Badrul Nizam Ismail,
R. Hussin,
Mohd. Nor Md. Yusuf,
Wan Nurulhuda Wan Shamsuri,
Karim Deraman,
S. Sholehah Hussein
Publication year - 2014
Publication title -
malaysian journal of fundamental and applied sciences
Language(s) - English
Resource type - Journals
ISSN - 2289-599X
DOI - 10.11113/mjfas.v8n2.129
Subject(s) - photoluminescence , plasma enhanced chemical vapor deposition , materials science , substrate (aquarium) , band gap , diamond like carbon , thin film , carbon fibers , spectroscopy , hydrogen , analytical chemistry (journal) , optoelectronics , nanotechnology , chemistry , composite material , physics , organic chemistry , oceanography , chromatography , quantum mechanics , geology , composite number
Diamond-like carbon (DLC) thin films were deposited at different substrate temperatures using methane and hydrogen gas in DC-PECVD at 2x10-1Torr. From the light transmission using UV-VIS spectroscopy it was found that the optical transition had changed from allowed indirect transition to allowed direct transition as the substrate temperature increased. The Optical gap increased with temperature, highest of 3.034 eV was observed at 573 K, beyond which it dropped. Colour of the film changed from light brownish to a colourless transparent film in the higher temperature. The Urbach energy decreased from 1.25 eV to 0.75 eV with increasing substrate temperature till 573 K and a slight increase after it. This trend is attributed to change in sp3/sp2 ratio or change in structure. The cluster size decreases with temperature, resulting in larger band gap and the structure more ordered. Similar pattern is also witnessed in the emission spectrum of the photoluminescence.
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