Characterization of a-C:H/W and a-C:H/Cr solar selective absorber coatings

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:194813

Gampp, R; Gantenbein, P; Kuster, Y ^[1]

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1. Univ. of Basel (Switzerland). Inst. of Physics; and others

Tungsten and chromium containing hydrogenated amorphous carbon films were deposited in a process which combines plasma activated chemical vapor deposition of methane and r.f.-sputtering of a metallic target. The metal content of the deposits can be adjusted by the ratio of gas flow between argon and methane and was determined by X-ray Photoelectron Spectroscopy (XPS). For the a-C:H/W composites the XPS data are presented in detail and supply information about the chemical state of carbon and tungsten. The presence of W in carbidic state could be proven. Furthermore the optical constants n and k of a-C:H/W were obtained in the wavelength range between 0.4 and 2.6 {mu}m and for W concentrations of up to 33 at.%. The morphology of the deposits, determined by atomic force microscopy, ranges from very porous to compact and can be controlled by the substrate bias voltage. Accelerated ageing investigations were performed in air in order to characterize the deterioration mechanisms of a-C:H/W and a-C:H/Cr films deposited on different substrate materials. The significance of the morphology of the coating and the roughness of the substrate for the ageing mechanisms could be shown. Very promising results concerning the film stability were obtained for a-C:H/Cr.

• OSTI ID: 194813
• Report Number(s): CONF-9404167--; ISBN 0-8194-1564-2
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
CARBON
CHROMIUM CARBIDES
COMPOSITE MATERIALS
ELECTRONIC STRUCTURE
HYDROGENATION
MORPHOLOGY
OPTICAL PROPERTIES
SOLAR ABSORBERS
SOLAR COLLECTORS
SPECTRALLY SELECTIVE SURFACES
TUNGSTEN CARBIDES