Fabrication of black silicon anti-reflection via nanocatalytic wet-chemical etch

ABSTRACT

Black silicon (b-Si) has been a subject of great interest in various fields including photovoltaics for its ability to reduce significantly the surface reflectance so that b-Si can absorb more than 98% of light signing on them. We have fabricated the b-Si anti-reflection via metal-assisted etching process using gold (Au) layer assisted nano-porous etching in this study. The b-Si layers were produced through a simple and effective method consist of a thin Au coating (d < 10 nm) that played as a catalyst layer onto Si (100) wafers prior immersion in a HF-H₂O₂-H₂O solution at room temperature, resulting catalyze formation of a network of [100]-oriented nanopores. The SEM observation suggested that the vertically columnar structure with a ∼300 nm deep nanopores layers can be formed in the limited synthesis conditions as well as achieved the extremely low reflectance about 2% at wavelength from 400–1000 nm.

KEYWORDS:

• Black Si
• wet chemical etch
• anti-reflection
• Au coating
• thickness