Surface morphology, structure and transport property of NaxCoO2 thin films grown by pulsed laser deposition

摘要

In this paper, we report the growth of NaxCoO2 thin films by pulsed-laserdeposition (PLD). It is shown that the concentration of sodium is verysensitive to the substrate temperature and the target-substrate distance due tothe evaporation of sodium during the deposition. alpha prime-phase Na0.75CoO2and gamma- phase Na0.71CoO2 thin films can be obtained with differentconditions. Correspondingly, the surface morphology of the films changes fromflake-like to particle-like. The temperature dependence of resistivity for thefilms prepared with the optimal condition shows metallic behavior, consistentwith the data of NaxCoO2 single crystals. This work demonstrates that PLD is apromising technique to get high quality NaxCoO2 thin films.