Microstructure and selected mechanical and electrical property analysis of Sr-doped LaCoO3 perovskite thin films deposited by the PLD technique

Abstract This work presents the results concerning microstructural, mechanical property and electrical resistance investigations of La1-xSrxCoO3 thin films produced by the laser ablation (PLD – Pulsed Laser Deposition) method on Si and MgO single crystal substrates with (001) orientation. The microstructure and chemical/phase composition analysis of the deposited films was carried out using scanning/transmission electron microscopy, X-ray diffraction and atomic force microscopy. Additionally, adhesion and nanohardness tests were performed. The investigations allowed verification of the quality of the prepared La1-xSrxCoO3 thin films and show that implementing the PLD technique makes it possible to obtain smooth and dense films with nanocrystalline structures, while preserving the composition of the bulk target. Research studies showed that by properly selecting the parameters for the PLD process it is possible to deposit films with a significantly lower amount and smaller size of undesirable nanoparticles. A specialized measuring station was used to determine the response of thin films to an oxidizing gas atmosphere. The observed decrease in resistance of the thin films in the presence of 50 ppm of NO2 oxidizing gas is typical for p-type semiconductors. This indicates that all of the produced films exhibit a sensitivity to this gas and could be used as NO2 sensors.