Quality control of epitaxial LiCoO₂ thin films grown by pulsed laser deposition

Thin films of c-axis-oriented LiCoO₂ were epitaxially grown by pulsed laser deposition (PLD). The ablation laser conditions greatly affect the crystal quality of the epitaxial LiCoO₂ thin films. In addition, high-quality LiCoO₂ thin films were found to grow without any impurity phases under relatively low oxygen partial pressure, although high pressure had been often selected to suppress the formation of Co₃O₄ with a lower valence state as an impurity. This result clearly indicates that the ablation laser conditions are an essential growth parameter, and that composition control is indispensable to grow high-quality complex compound thin films by PLD.