IR absorptance of thin carbon multi-walled nanotubes layers

The IR transmittance and reflectance spectra of thin films which consist of multi-walled carbon nanotubes (MWCNT) are measured in the range from 2 to 17 μm. The MWCNT films of various thicknesses not exceeding 1.2 μm were deposited on silicon substrates with Si3N4/Al2O3 dielectric layers. It is shown that the deposition of an Al2O3 layer with a thickness of 2 nm allows to significantly improve the homogeneity and continuity of the MWCNT films. A technique is proposed for measuring the average thickness of rough MWCNT films by means of atomic force microscopy after laser engraving. Suggested method of spectra processing allows to estimate the spectral dependence of the IR radiation absorptance in MWCNT films, which are diffusely scattering objects and have a large absorption coefficient.