Hybrid Chemical Vapor Deposition/Sol−Gel Route in the Preparation of Nanophasic LaCoO3 Films

Lanthanum cobaltite (LaCoO 3 ) thin films were synthesized by an innovative route based on the combination of chemical vapor deposition (CVD) and sol−gel (SG) methods. In particular, the approach is based on the sequential deposition of binary oxide systems (Co−O on La−O) and on the ex situ thermal treatment of the final product ( T = 400−900 °C, t = 1−8 h), aimed at favoring solid-state reactions for the formation of a ternary La−Co−O nanosystem. To highlight the peculiar effects of these procedures on the characteristics of the final product, both SG and CVD routes were used for the preparation of single-phase La−O and Co−O species. The process resulted in the formation of LaCoO 3 nanostructured films with an average crystallite size lower than 20 nm. The required processing conditions were strongly dependent on the specific synthetic pathway: (i) SG of Co−O on CVD La−O; (ii) CVD of Co−O on SG La−O. In this framework, particular attention was focused on the analogies and differences between the two sequences and on a study of the most relevant compositional, structural, and morphological system features.