“…As a dielectric metal oxide, Al 2 O 3 exhibits a high transparency, large bandgap and excellent electrical insulation properties, hence it is widely applied in electronic devices and electrochemistry, e.g., as a protection layer [1,2,3,4,5,6]. Commonly used methods for making Al 2 O 3 films include sol-gel, sputtering, evaporation, physical vapor deposition (PVD), chemical vapor deposition (CVD) and atomic layer deposition (ALD) [7,8,9,10,11]. CVD is a widely used thin film deposition technique to provide good quality thin films with control over the chemical composition.…”