Black silicon

Black silicon is a semiconductor material, a surface modification of silicon with very low reflectivity and correspondingly high absorption of visible (and infrared) light.

The modification was discovered in the 1980s as an unwanted side effect of reactive ion etching (RIE). Other methods for forming a similar structure include electrochemical etching, stain etching, metal-assisted chemical etching, and laser treatment.

Black silicon has become a major asset to the solar photovoltaic industry as it enables greater light to electricity conversion efficiency of standard crystalline silicon solar cells, which significantly reduces their costs.