Applied Surface Science, Vol.360, 540-546, 2016
Chemical vapor deposition of low reflective cobalt (II) oxide films
Low reflective CoO coatings are processed by chemical vapor deposition from Co-2(CO)(8) at temperatures between 120 degrees C and 190 degrees C without additional oxygen source. The optical reflectivity in the visible and near infrared regions stems from 2 to 35% depending on deposition temperature. The combination of specific microstructural features of the coatings, namely a fractal "cauliflower" morphology and a grain size distribution more or less covering the near UV and IR wavelength ranges enhance light scattering and gives rise to a low reflectivity. In addition, the columnar morphology results in a density gradient in the vertical direction that we interpret as a refractive index gradient lowering reflectivity further down. The coating formed at 180 degrees C shows the lowest average reflectivity (2.9%), and presents an interesting deep black diffuse aspect. (C) 2015 Elsevier B.V. All rights reserved.