Pulsed laser deposition of the ion-conducting LiCoO₂ films

Pulsed laser deposition on the n-type and p-type sapphire and silicon substrates produced the ion-conducting LiCoO₂ films with a thickness of 10 to 100 nm. The films were synthesized from the compound LiCoO₂:Li₂O targets with the concentrations of Li₂O 5% and 10% at the substrate temperature of 25 to 500 °C. The optical and electrical properties and surface morphology of the films obtained were investigated depending on the type of the substrate and the deposition temperature. The surface roughness of the LiCoO₂ films weakly depended on the type of substrate and increased from 7 to 35 nm with a decrease in the substrate temperature from 500 to 25 °C, respectively. The transmission of the LiCoO₂ films increased, on the average, by 30% over the entire spectral range under study from 200 to 1000 nm with a change in the substrate temperature from 25 to 500 °C. It has been established that the LiCoO₂ films deposited on the silicon substrates exhibit the resistivity of the order of 10⁻⁷ Ω cm for the films prepared on high-conducting n- and p-type silicon, and of the order of 10^-1 Ω cm for those prepared on high-resistance silicon of n-type. The LiCoO₂ films deposited on the c-sapphire substrates display dielectric properties.