Thin Films of Ionic Condductors by laser Ablation

摘要

Films of isertion compounds and solid state electrolytes have been synthesized in order to study their applciations in the domain of elctrochemical ion and gas sensors. Laser ablation was used to deposit lithium metal oxides. The chemical composition in the films has been stuided by Rutherford Backscatering spectrometry nad nuclear reactions anaysis in the cae ofthe light elements. For lithium transitio metal oxides, the oxygen and lithium contents are determined by a thermodynamical equilibrium between the films and the partial pressures in the chamber.IN these cases, alser ablation allows the synthesis of crystalline sructures wiht a large range of oxygne non stoichiometry as compared to solid state reactions. They lead to interesting electrical propeties. Using the appropriate temperatures and oxygen pressures, films with the corect stoichiomentry could be obtained as polycrystalline onto Si or Si/Pt substrrates whereas they exhibit high texturing and epitaxial growth onto MgO or MgO/Pt. The films of LiMN_2O_4 and LiCoO_2 have been used as electrochemical sensors for the measurement of the lithium concentration in solutions. They show a very rapid and selective response.