Optimized process of metal assisted silicon wet etching for antireflection layer

► A simple fabrication technique for silicon subwavelength structure is proposed. ► Au nanoparticles are an excellent catalyst to wet etching. ► Au nanoparticles were fabricated using the metal self-aggregation effect. ► Particle size was adapted with initial Au film thickness before annealing. ► Reflectance of etched Si was almost 0% for the wavelength from 300 to 1300 nm.