The origin of low water vapor transmission rates through Al₂ O₃ / ZrO₂ nanolaminate gas-diffusion barriers grown by atomic layer deposition

This paper reports on thin film gas-diffusion barriers consisting of Al₂ O₃ / ZrO₂ nanolaminates (NL) grown by low-temperature (80°C) atomic layer deposition. We show that reliable barriers with water vapor transmission rates of 3.2× 10-4 g/ (m ² day), measured at 80°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 Al₂ O₃ and ZrO₂ sublayers, which additionally improves the gas-diffusion barrier due to a densification of the layer system. These Al₂ O₃ / ZrO₂ NLs prepared at low temperatures hold considerable promises for application in organic electronics and beyond.