Macroporous Silicon Fabricated by HF Electrochemical Etching for Antireflective Application in Solar Cells

Macroporous silicon was fabricated by electrochemical etching in hydrogen fluoride (HF) electrolyte on P-type silicon wafers. By optimizing the etching condition, the obtained macroporous silicon presented pore diameter of about 2 μm and pore density of ~107/cm2. Such macroporous silicon gave out an excellent antireflective performance with the reflectance lower than 4% in a wide spectral range of 400-1000 nm. An a-Si:H/c-Si heterojunction solar cell was fabricated on such macroporous silicon to show its application potential.