Structural analyses of submicron LiCoO2 films

Submicrometer LiCoO2 films were prepared with pulsed laser deposition (PLD) and rf sputtering using stoichiometric targets. The influences of both substrate material and annealing procedure on the polycrystalline microstructure of the LiCoO2 films were investigated. XRD analysis revealed strong preferential orientation: annealed films deposited with PLD had their (00l) planes parallel to the surface, while rf sputtered films had their (110) planes in this orientation. The rf-film also developed the (003) reflection typical of PLD-films, but only after prolonged annealing at 600°C. The degree of preferential orientation is influenced significantly by the annealing procedure and only little by the substrate material and the thickness of the deposited film. Pulsed laser deposition on an rf-sputtered seed layer revealed the PLD-film reflections. Extinction of the otherwise dominating (003) reflection indicated a random cationic distribution in LiCoO2 with an NaCl-type structure