Translator Disclaimer
25 November 1992 Properties of spectral selective Nb films
Author Affiliations +
Spectrally selective absorption coatings for solar thermal energy conversion applications should exhibit a high absorptance in the 0.4 - 1 micrometers wavelength range of the electro magnetic spectrum. Additionally, a low emittance in the thermal radiation range has to be attained. Niobium films displaying such optical properties were obtained by sputtering onto Si(100) and Mo substrates and suitable variation of the preparation parameters. The sputtered films were characterized by in situ photoelectron spectroscopy, and not in situ optical reflectometry and scanning electron microscopy (SEM). Emittance and absorptance were determined as function of temperature by the `dynamical vacuum technique.' It is found in particular that the as prepared films show a dendritic surface structure as revealed by SEM. In addition, the wavelength of transition from highly absorbing to reflecting character is shown to correlate with the inter-dendrite distance.
© (1992) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
J. Eitle, P. Gantenbein, Hans Peter Lang, P. Oelhafen, E. Zuberbuehler, D. Mathys, and Richard Guggenheim "Properties of spectral selective Nb films", Proc. SPIE 1727, Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XI: Selective Materials, Concentrators and Reflectors, Transparent Insulation and Superwindows, (25 November 1992);


Back to Top