A double-layer structure of Al₂O₃ over ZrO₂ film is studied. Minimization of the average weighted reflectance is carried out to optimize the thickness of the two layers in the antireflection coating. An optimal value of 2.17% for the weighted average reflection is estimated. The optimal thicknesses of the layers are 49 nm for the bottom and 45 nm for the top layer. Low temperature spin coating technique is used to deposit ZrO₂ and Al₂O₃ films from sol gel solutions on polished silicon wafers, GaAs multilayer heterostructures and AlGaAs/GaAs solar cells. The density of the short-circuit photocurrent increases from 25 mA.cm⁻² for solar cells without an antireflection coating to 36 mA.cm⁻² for those with a double layer coating.