Three-dimensional dual-porous structure developed by preferentialstain etching on grind-damaged (001) Si: Formation and optical properties

The dual-porous-structure (DPS) consisting of the amorphous porous structure (APS) and the defect-followed mesoporous structure (DMPS) was created using a new method combining the preferential etching and the stain etching on a grind damaged (001) silicon wafer. In this article, this novel pore-structuring technology, utilizing prominent reactivity of the intentional defect site produced by grind process, is introduced, and its procedures and the structural behaviors of the DPS are described by atomic force microscopy, transmission electron microscopy, scanning electron microscopy and 3D-profiling. Analysis of the optical properties proves that the broad photoluminescence intensity exists in the whole visible spectral range, and the light trapping functions of the antireflective coating and surface texture come from the APS and the DMPS, respectively. We also attempt to discuss about the absorption edge shift to the NIR spectral region using oblique angle of the DMPS. This original defect engineering approach is situated on viability of a rapid large area pore-structuring technology, and the optical properties were experimentally described for the first time.