Deposition and Electrical and Structural Properties of La0.6Sr0.4CoO3 Thin Films for Application in High-Temperature Electrochemical Cells

Abstract

Low-temperature deposition of electroceramic thin films allows the construction of new devices and their integration with existing large-scale fabrication methods. Developing a suitable low-cost deposition method is important to further advance the development of microdevices. In this work, we deposited a 1-μm-thick La0.6Sr0.4CoO3−δ (LSC) perovskite with high electrical conductivity on sapphire substrates at 400°C and analyzed its electrical, morphological and structural properties as a function of temperature in the range of 400–1100°C. The results show that spray pyrolysis can be used to deposit high-quality reproducible layers with the desired chemical and phase composition. Upon heating to around 600°C, the residual C–O and C=O species are removed, and the deposited layers crystallize and become conducting. The dependence of electrical conductivity versus processing temperature has a complex character—the maximum conductivity is found for layers processed at 800°C. An analytical model of stress distribution was used to predict stress to which the bi-layer material would be exposed to while being cooled down from the annealing temperature to room temperature. The high electronic conductivity and high-quality microstructure of the LSC layers, which can be adjusted with the appropriate heat treatment procedure, make them suitable for applications in electrochemical devices applied in integrated energy modules, including electrodes or contacts.