The effect of nitrogenation on the IR optical constants of amorphous hydrogenated carbon layers

Abstract

Nitrogenated amorphous carbon layers have been deposited by a dc plasma technique on silicon substrates. The optical constants of the film material have been determined from spectrophotometric measurements in the MIR/NIR spectral ranges. Special attention was paid to the parameters of the exponential absorption tail. The layers have been found to have IR refractive indices around 1.9. They are MIR transparent while showing considerable absorption in the NIR. Therefore, they may be of interest for the design of spectrally selective solar absorber coatings.