Spectroscopic properties of nitrogen doped hydrogenated amorphous carbon films grown by radio frequency plasma-enhanced chemical vapor deposition

Journal Article · Fri Jun 15 04:00:00 EDT 2001 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1371268· OSTI ID:40204204

Hayashi, Y; Yu, G; Rahman, M M; Krishna, K M; Soga, T; Jimbo, T; Umeno, M

Nitrogen doped hydrogenated amorphous carbon thin films have been deposited by rf plasma-enhanced chemical vapor deposition using CH{sub 4} as the source of carbon and with different nitrogen flow rates (N{sub 2}/CH{sub 4} gas ratios between 0 and 3), at 300 K. The dependence modifications of the optical and the structural properties on nitrogen incorporation were investigated using different spectroscopic techniques, such as, Raman spectroscopy, Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, ultraviolet-visible (UV-VIS) spectroscopy, electron spin resonance (ESR), photoluminescence (PL) and spectroscopic ellipsometry (SE). Raman spectroscopy and IR absorption reveal an increase in sp{sup 2}-bonded carbon or a change in sp{sup 2} domain size with increasing nitrogen flow rate. It is found that the configuration of nitrogen atoms incorporated into an amorphous carbon network gradually changes from nitrogen atoms surrounded by three ({sigma} bonded) to two ({pi} bonded) neighboring carbons with increasing nitrogen flow rate. Tauc optical gap is reduced from 2.6 to 2.0 eV, and the ESR spin density and the peak-to-peak linewidth increase sharply with increasing nitrogen flow rate. Excellent agreement has been found between the measured SE data and modeled spectra, in which an empirical dielectric function of amorphous materials and a linear void distribution along the thickness have been assumed. The influence of nitrogen on the electronic density of states is explained based on the optical properties measured by UV-VIS and PL including nitrogen lone pair band. {copyright} 2001 American Institute of Physics.

• Sponsoring Organization: (US)
• OSTI ID: 40204204
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 12 Vol. 89; ISSN 0021-8979
• Publisher: The American Physical Society
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARBON
CHEMICAL VAPOR DEPOSITION
DIELECTRIC MATERIALS
ELECTRON SPIN RESONANCE
FLOW RATE
NITROGEN
OPTICAL PROPERTIES
PHOTOELECTRON SPECTROSCOPY
RAMAN SPECTROSCOPY
THIN FILMS