Read the dissertation: Hierarchical black silicon and their applications.
Black silicon, as a family member of silicon semiconductor materials, has a unique light-trapping capability and presents deep "black" colour. The black surface traps visible light through internal multi-reflection, scattering, and light-matter coupling due to micro/nano silicon structures, such as pores, pillars, cones, needles, and wires. Mr. Zhang invented novel black silicon with hierarchical surface textures using a self-developed two-step etching approach and a modified Bosch process. Hierarchical surface textures are composed of micropores/hollow cylinders decorated with nanopores on top and were named honeycomb and chimney-like black silicon. Such kinds of black silicon show outstanding antireflection of lower than 0.5% in the 200 to 1100 nm wavelength range.
Furthermore, the hierarchical texture joins hands with specific-size Au nanoparticles to synergize excellent antireflection of <1% to optical waves from 200 to 2600 nm. In addition, this project explored the fabricated black silicon's performance in photo-thermal-electric, photoelectric, and super-hydrophobic fluid control.