The Al₂O₃/TiO₂ double antireflection coating deposited by ALD method

Al₂O₃/TiO₂ thin films were deposited onto monocrystalline silicon surfaces using an atomic layer deposition. Their surface morphology and optical properties were examined for their possible use in solar cells. The surface condition and chemical composition were characterized using a scanning electron microscope and the thickness was measured using a spectroscopic reflectometer. The refractive index and the reflection characteristics were determined. First, the optical properties of the Al₂O₃ thin filmand its influence on recombination in the semiconductor were examined. In this way, it can fulfil a double role in a solar cell. Since reflection reduction was only achieved in a narrow range, it was decided to use the Al₂O₃/TiO₂ system. Thanks to this solution, the light reflection was reduced in a wide range (even below 0.2%).