Fabrication of polycrystalline aluminum oxide thin films via hydrolysis and hydrothermal reactions in solutions

Polycrystalline Al2O3 thin films were fabricated through a method combining urea hydrolysis and hydrothermal reactions. The overall growth temperature of these films was achieved as low as 150 °C. Although cracks occurred across the gel film after hydrolysis, a subsequent nucleation under elevated pressure and temperature resulted in a closely packed morphology. Moreover, the hydrothermal treatment led to high oxide content and an increase in crystallinity within the films.