Preparation of porous silicon by electrochemical etching methods and its morphological and optical properties

Abstract

Porous silicon (PS) has been widely used in solar cells and photodetectors because of its very low reflectance. However, its properties are greatly influenced by its morphological characteristics. In this work, PS samples with different morphologies were prepared by electrochemical etching with different fabrication parameters (etching time, current density, and solution composition). There were cracks microstructures on the surface of PS and their shapes were affected by different fabrication parameters. A crack model was established to analyze the formation mechanism of the surface morphology. The influence of different fabrication parameters on the surface morphology and the infrared spectrum of PS were analyzed. The morphological and optical properties of PS with a composite structure were studied. The results indicated that PS with composite structure can promote the oxidation reaction while significantly reducing the reflectance.