Optical emission spectroscopy study on deposition process of microcrystalline silicon

Sunlight loss for femtosecond microstructured silicon with two impurity bands

“…[1] Researchers found that this new material had several unusual optical properties such as strong absorption of light with wavelength from 0.25 µm to 17 µm [2] and nice field emission characteristics; therefore, they predicted that black silicon had incomparable superiority to other materials in the solar cell field. Research results indicate that the enhanced visible light absorption of black silicon is mainly due to the multi-reflection caused by the periodic structure on its surface while the strong infrared absorption is mainly due to the deep energy levels, [3,4] which consist of impurities and defects introduced by laser-assisted chemical etching [5−8] within the band gap. Chalcogen is reported to be able to introduce impurity levels into the band gap of silicon.…”