Nitrogenation of amorphous carbon layers as a method for improving their performance as a spectrally selective absorber coating

Nitrogen-containing amorphous hydrogenated carbon layers have been deposited on silicon and aluminum by a dc plasma technique. The optical constants of the layers (refractive index and absorption coefficient), their solar absorptance and the thermal emittance at 373 K have been determined from spectrophotometric measurements. It is demonstrated that the solar absorptance of nitrogenated layers is higher than that of corresponding pure amorphous hydrogenated carbon layers, while the emittance values are comparable.