Greatly enhanced infrared normal spectral emissivity of microstructured silicon using a femtosecond laser

The infrared normal spectral emissivity of microstructured silicon prepared by femtosecond laser irradiation in SF6 was measured for the wavelength range 2.5 mu m to 25 mu m. Greatly enhanced emissivity compared to that of flat silicon was observed over the entire wavelength range. For a sample with 13-14 mu m high spikes, the emissivity at a temperature of 100 degrees C is approximately 0.96. The emissivity decreases slightly in the wavelength region above 8 mu m, but remains higher than 0.9 over most of the measured wavelength range. Also the average emissivity is less than Nextel- Velvet-811-21 Coating, it can be used stably at more wide temperatures from 100 degrees C to 400 degrees C. These results show the potential for microstructured silicon to be used as a flat blackbody source or silicon-based pyroelectric and microbolometer devices. (C) 2011 Elsevier B.V. All rights reserved.