Silicon is the material of computer chips and solar cells. It is ubiquitous throughout the high-tech world. Ordinarily, silicon absorbs a moderate amount of visible light, but a substantial amount of visible light is reflected as well, and infrared and ultraviolet light are transmitted through silicon or reflected from it with very little absorption.
Black silicon is made by shining a series of very short, very intense laser pulses at a silicon surface in a chamber filled with sulfur-rich gas. Black silicon, in contrast, absorbs nearly all light at wavelengths ranging from the ultraviolet to the infrared. This suggests it may be very useful in improving the performance of existing silicon devices, such as detectors and photovoltaics.