The origin of low water vapor transmission rates through Al2O3/ZrO2 nanolaminate gas-diffusion barriers grown by atomic layer deposition

This paper reports on thin film gas-diffusion barriers consisting of Al2O3/ZrO2 nanolaminates (NL) grown by low-temperature (80 degrees C) atomic layer deposition. We show that reliable barriers with water vapor transmission rates of 3.2x10(-4) g/(m(2) day), measured at 80 degrees C and 80% relative humidity, can be realized with very thin layers down to 40 nm. We determine that ZrO2 acts as anticorrosion element in our NL. Furthermore, we demonstrate by x-ray photoemission spectroscopy that an aluminate phase is formed at the interfaces between Al2O3 and ZrO2 sublayers, which additionally improves the gas-diffusion barrier due to a densification of the layer system. These Al2O3/ZrO2 NLs prepared at low temperatures hold considerable promises for application in organic electronics and beyond. (C) 2010 American Institute of Physics. [doi:10.1063/1.3455324]