Chemical vapor deposition of low reflective cobalt (II) oxide films

Eliane Amin-Chalhoub (1) , Thomas Duguet (1) , Diane Samélor (1) , Olivier Debieu (1) , Elisabeta Ungureanu (1) , Constantin Vahlas (1)

1 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux

Low reflective CoO coatings are processed by chemical vapor deposition from Co2(CO)8at temperatures between 120◦C and 190◦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◦C shows the lowest average reflectivity (2.9%), and presents an interesting deep black diffuse aspect.

Mots clés: Optical reflectivity; MOCVD; Refractive index gradient; CoO; Cobalt oxide

Domaines: Matériaux; Matériaux

Eliane Amin-Chalhoub, Thomas Duguet, Diane Samélor, Olivier Debieu, Elisabeta Ungureanu, et al.. Chemical vapor deposition of low reflective cobalt (II) oxide films. Applied Surface Science, 2016, 360, pp.540-546. ⟨10.1016/j.apsusc.2015.10.188⟩. ⟨hal-01264368⟩