On the use of black silicon obtained by reactive ion etching as the hot spot of a thermoelectric generator heated by electromagnetic radiation

In this paper, we study the enhancement of silicon absorbing properties while microstructuring its surface with cones of variable size and spacing. We simulate the optical reflectance of the structures with spikes of different dimensions. Then random maskless textured silicon, called “black silicon” is processed by reactive ion etching (RIE) under cryogenic temperatures. Using this process, three different black silicon substrates with micro and sub-micro spikes are obtained and are found to exhibit excellent anti-reflective behavior over the 350-1100 nm spectral range. Reflectance measurement with an integrating sphere is around 1% in the visible range.