Electrostatic Gating of Aligned Carbon Nanotube Films for Terahertz Modulation

Terahertz (0.1–3 THz) frequencies offer a wide bandwidth for future wireless and sensing technologies, but their application is limited by the absence of compact, tunable modulators [1]. Carbon nanomaterials provide a route to ultrathin, voltage-controlled THz devices through their unique optical anisotropy and carrier tunability [2,3]. We report progress on gated aligned single-wall carbon nanotube (SWCNT) films integrated with HfO₂ dielectric layer, achieving low-leakage and stable electrostatic operation. Free-space THz time-domain spectroscopy reveals strong polarization dependence and reproducible gate-bias-induced variations in transmission, consistent with the anisotropic optical conductivity of aligned CNT networks. These results demonstrate reliable electrical gating in macroscopic CNT films, establishing a foundation for future studies of active THz modulation, carrier dynamics, and polarization control in low-dimensional nanomaterial systems.