Other
Scientific paper
Jan 1993
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993aas...18111611f&link_type=abstract
American Astronomical Society, 181st AAS Meeting, #116.11; Bulletin of the American Astronomical Society, Vol. 25, p.735
Other
Scientific paper
We present the initial results of a laboratory study of hydrogenated amorphous carbon (HAC) thin films. We produce a quantitative summary of the optical and physical properties of a consistent set of HAC films processed in various ways and use these results to gain insight into the formation and evolution of dust grains in the interstellar medium. HAC thin films were deposited on NaCl coated substrates in a plasma-enhanced chemical-vapor deposition (PECVD) chamber, removed from the substrates, and characterized and processed in a variety of ways. Raman, photoluminescence (PL), transmission, and absorption spectroscopy were used to characterize these films in the visible. Infrared absorption and PL spectroscopy were used to analyze these films in the 1-20 micron region. Electron energy-loss spectroscopy (EELS) was used to calculate the index of refraction in the UV and the sp(2}/sp({3)) bonding ratio, and combustion analysis was used to determine the C/H ratio. Each member of a set of identically grown films was characterized as described above, processed to various extents, then characterized again. Some of the films were thermally annealed in vacuum over a range of temperatures and durations, while others were exposed to intense UV radiation. Our initial results are summarized as follows: The H-concentration, PL efficiency, band-gap, and transmission in the visible decrease with the extent of thermal or UV annealing. Thermally induced changes occur rapidly and long-term annealing at lower temperatures does not produce the same effects as higher temperature annealing. The films are essentially graphitized when annealed at temperatures higher than about 400(deg) C and they are completely obliterated when exposed to very intense UV radiation. We have also developed a thermal effusion oven to test to what extent HAC films can be ``rehydrogenated'' by exposure to neutral atomic hydrogen. These experiments are nearly complete and the results will be included if possible. This work is funded by NASA grant # NAGW-2794 to the University of Toledo.
Furton Douglas G.
Witt Adolf N.
No associations
LandOfFree
The Optical Properties of Hydrogenated Amorphous Carbon Films does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Optical Properties of Hydrogenated Amorphous Carbon Films, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Optical Properties of Hydrogenated Amorphous Carbon Films will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1772415