Texture etching of monocrystalline silicon surface with sodium hypochlorite

Silicon etching in alkaline solutions has been employed for many years, in the fabrication of solar cells. Surface texturisation of crystalline silicon was performed by using different etching solutions. Recently, a strong oxidising reagent NaOCl has been used successfully by several authors to texture the silicon surface. In this work, the effect of the etching parameters such as solution composition on the silicon surface morphology is studied. The surface of etched samples was analysed by scanning electron microscopy (SEM), spectrophotometry and secondary ion mass spectroscopy (SIMS). The results clearly show that the presence of ethanol in the solution leads to the formation of pyramids, while its absence induces the formation of nanostructures (nanowire or nanoneedle).