NIR and MIR Absorption of Ultra-Black Silicon (UBS). Application to High Emissivity, All-Silicon, Light Source

We present the Near-Infra-Red (NIR) and Mid-Infrared (MIR) absorption properties of Ultra-Black Silicon obtained by wafer-level cryogenic plasma processing. We found that when using highly-doped silicon, the spectral range of near-unity full absorption of light is extended from the visible range till a wavelength of 10 μm. This MIR wavelength range coincides with that of the maximum of black-body radiation from room temperature up to a few thousand Kelvin. Therefore, according to Kirchhoff's Law, we take advantage of the enhanced properties of black silicon to realize ultra-compact light-sources of high efficiency, which are operated in combination with a MEMS-FTIR spectrometer.