Choi, S Lee, KR Oh, SG Lee, S 2024-01-21T13:01:27Z 2024-01-21T13:01:27Z 2021-09-05 2001-01-15 0169-4332 https://pubs.kist.re.kr/handle/201004/140773 Hydrogenated amorphous carbon (a-C:H) films were deposited on-double-side polished germanium substrates by RF plasma-assisted chemical vapour deposition method using benzene as a precursor, and their optical properties were investigated in the wavelength range from 700 nm to 10 mum. In particular, we used a dispersion-function-based non-linear regression to fit the reflectance in the range from 700 to 1800 nm and the baselines of the infrared transmittance in the range from 1000 to 5000 cm(-1), respectively. Optical constants determined in both ranges, together with their respective thickness values, showed overall consistency. As a function of self-bias, we found that the refractive index increased while the band gap decreased, which was indicative of film densification and increase of sp(2)-bonded carbons. Detailed information on the self-bias-dependent evolution of microscopic bonding structure in a-C:H films was revealed via the quantitative vibration-absorption spectra in the mid-infrared region, which was obtained after taking Urbach-tail-like electronic absorption into consideration. More specifically, it was found that as self-bias was increased hydrogen content decreased, olefinic sp(2)-bonding decreased while aromatic sp(2)-bonding increased, and more carbon bonding was distorted due to increased cross-linking. Maximum sp(2)-bonding was observed between -300 and -400 V of self-bias. (C) 2001 Elsevier Science B.V. All rights reserved. English ELSEVIER SCIENCE BV DIAMOND-LIKE CARBON Wide wavelength-range optical studies of hydrogenated amorphous carbon films: from 700 nm to 10 mu m Article 10.1016/S0169-4332(00)00654-1 1 APPLIED SURFACE SCIENCE, v.169, pp.217 - 222 APPLIED SURFACE SCIENCE 169 217 222 scie scopus 000167087700044 2-s2.0-18844479557 Chemistry, Physical Materials Science, Coatings & Films Physics, Applied Physics, Condensed Matter Chemistry Materials Science Physics Article; Proceedings Paper DIAMOND-LIKE CARBON dispersion function infrared absorption spectroscopy hydrogenated amorphous carbon reflectance transmittance