Theoretical and Numerical Investigation of Electromagnetic Absorption in Carbon Nanotube/Pyrolytic Carbon Hybrid Nanocomposites in the Terahertz Regime

Abstract

Advanced nanomaterials for terahertz (THz) electromagnetic (EM) wave absorption are essential for emerging 6G communications, sensing, and aerospace applications. This work presents a theoretical and numerical investigation of a novel hybrid nanocomposite consisting of carbon nanotubes (CNTs) embedded in a pyrolytic carbon (PyC) matrix. The complex permittivity and EM absorption were modeled over the 0.1–10 THz frequency range using the Maxwell-Garnett effective medium theory, considering the frequency-dependent conductivity and depolarization effects of high-aspect-ratio CNTs. The proposed hybrid structure exhibits a clear synergistic enhancement in absorption compared with pure PyC. A maximum absorption of 49.98% was achieved at a 30% CNT volume fraction in a 25 nm ultrathin film, while pure PyC reached 43.53%, corresponding to a relative improvement of 14.83%. Energy conservation was verified across the investigated frequency range, confirming the accuracy of the theoretical model. The results demonstrate that incorporating CNTs into a PyC matrix significantly improves THz absorption and provides a predictive framework for optimizing carbon-based hybrid nanocomposites. The proposed design offers a promising route for developing efficient ultrathin THz absorbers for future high-frequency technologies.