Anti-reflective coatings of flowerlike alumina prepared by sol-gel process with hot water treatment

Abstract

Al₂O₃ gel films heated at 400°C were immersed in hot water at 100°C to give the flowerlike structure with a small roughness of about 50-80 nm on the surface. The thin film showed the anti-reflection property. The reflection of the f flowerlike Al₂O₃ film was less than 0.5% at wavelength region of 220-620nm. Further more at wavelength region of 270-320nm, the reflectance was less than 0.2%. Anti-reflection effect of the coating was improved by the control of the thickness of the films and the hot water treatment time.