Optical properties of Diamond like Carbon films prepared by DC-PECVD
Keywords:Diamond like carbon, Optical properties, DC-PECVD, Optical gap, Urbach Energy,
AbstractDiamond-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.
A. Grill. Diamond and Related Materials, 8 (1998), 428–434.
Rusli, Amaratunga, A.J. and Silva, S.R.P. Diamond and Related Materials, 3 (1994)817-820.
K.B.K.Teo,A.C.Ferrari,G.Fanchini,S.E.Rodil,J.Yuan,J.T.H.Tsai,E.laurenti,A.Tagliaferro,J.Robertson,W.I.Milne. Diamond and Related a Materials,11 (2002)1086-1090.
F.A.Mahmoud,SH.SH.Saresmbinov,O.Yu.Prikhodko,andA.P.Ryaguzova. Journal of Ovonic research, 6(2010)253-257
A. Abdelghany, S N Elsayed, A H Abou El Ela and N H Mousa,Pergamon. 0041-207X(1995)00210-3
J. Robertson, National Power Laboratory, Leatherhead Surrey, 22 (1991) 7.
C.W. Chen, J. Robertson, Journal of Non-Crystalline Solids ,227–230 (1998) 602–606.
R.Gago, N.Huangc, M.P Kulish, U. Kreissig, Y.X. Leng, M.F. Maitz, H.Sunc, and Vinnichenko, Thin Solid Films. 455 –456 (2004) 530–534
J. Robertson, Diamond and Related Materials, 12(2003)79-84.
G. Tagliaferro., Fanchini., Diamond and Related Materials ,13 (2004) 1402–1407
A. Ates, B. Gurbuluk., M. Yildirim, S. Dogan, T.