Optical properties of CrCo oxide films obtained by chemical spray deposition: Substrate temperature effects

• Published in: Thin solid films Vol. 77; no. 1; pp. 99 - 106
• Main Authors: Noguchi, S, Mizuhashi, M
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.1981
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/0040-6090(81)90364-3

The relation between the transmission colour of mixed oxide films consisting of chromium and cobalt oxides and the condition of the spray deposition on heated glass substrates was investigated using solutions containing chromium acetylacetonate (Cr(AA) 3) and cobalt acetylacetonate (Co(AA) 3). The colour of the films was found to be critically dependent on the substrate temperature; a brownish film was obtained at 500°C, a greenish film at 580°C and a bluish-green film at 60°C in the case of the solution containing 0.3 moll −1 Cr(AA) 3 and 0.1 moll −1 Co(AA) 3. These colour changes were closely related to the Co:Cr atomic ratio in the films. From the experiments on pure oxides it was found that the deposition rate of chromium oxide had a very strong dependence on the substrate temperature in the temperature range 500–660°C. The compositional variation expected from this temperature dependence in the direction perpendicular to the film plane owing to the decrease of surface temperature during the spray deposition was verified by depth profile analysis Auger electron spectroscopy. The optical absorption analysis the suggested the existence of tetrahedral Co 2+ ions in the greenish film. This speculation was confirmed by the average Co:Cr atomic ratio of about 0.5, which is the stoichiometric ratio of CoCr 2O 4 spinel.