Abstract
This work presents the synthesis of carbon nanofilaments obtained through the decomposition of graphite in methane plasma with argon admixture. The resulting nanostructures exhibit an amorphous configuration and remain transparent across the visible spectrum, making them attractive candidates for optical and optoelectronic applications. Atomic force microscopy revealed that the filaments form a compact, vertically oriented network on the substrate surface, while Raman spectroscopy provided information on their local bonding environment. Morphologically, the carbon filaments display flattened, ribbon-like forms, and their densely packed columnar structures reach an average length of ~36 nm. The optical transmission spectrum showed transmittance of ~65% near 400 nm, ~75% within the visible region, and nearly 80% in the near-infrared range, gradually increasing toward longer wavelengths. This degree of transparency in the visible spectrum is sufficient for practical device applications. When the incident light wavelength is comparable to or smaller than the inter-filament spacing (100–500 nm), light propagation occurs through reflections from the filament walls. The optical band gap of the structures was determined to be ~2.85 eV. Overall, the analysis of structural and optical properties confirms the successful fabrication of amorphous carbon nanofilaments, highlighting their strong potential for integration into advanced optoelectronic systems.