, La 1ère Ecole d’Automne sur les Matériaux Emergents(EAME)

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Morphological and X-Ray Photoelectron Spectroscopy Characterization of Al2O3 and Al:ZnO Coated Black Silicon (100) by Atomic Layer Deposition

Dernière modification: 2017-11-15


The high refractive index of silicon requires efficient broad band anti-reflection (AR) measures to reduce Fresnel reflection losses. Commercial standard silicon solar cells rely on surface textures created by random anisotropic etching, which still is time-consuming and only applicable to the monocrystalline material. At this stage, the black silicon fabricated by ICP-RIE could offer a solution that combines both broadband AR properties and strong near band gap light trapping. The optical and electronic properties of monocrystalline Si (100) with a nanostructured surface obtained by an inductively coupled plasma (ICP) dry reactive ion etching (RIE) process in a gas mixture of SF6 and O2, were improved with regard especially to solar cell applications. Al2O3 and Al:ZnO thin films were grown on highly doped p-Si (100) and n-Si (100) black silicon respectively by atomic layer deposition (ALD) using trimethylaluminum (TMA) and water as precursors for Al2O3 thin film, and methylzincisopropoxide (MZI), dimethylaluminium isopropoxide (DMAI) and water as precursors for Al:ZnO thin film. The morphology of the deposited films and initial black silicon (silicon grass) were investigated by means of reflection electron microscopy (REM). X-ray photoelectron spectroscopy (XPS) was used to analyze the chemical elemental composition by observing the behavior (stoichiometry) of the Zn 2p, Al 2p, O 1s and C 1s lines of three samples. Binding energy analysis and calculated Auger parameter confirmed the formation of conformally Al2O3 and Al:ZnO on the black silicon samples.