Terahertz optical and electrical properties of hydrogen-functionalized carbon nanotubes

This study characterized hydrogen-functionalized carbon nanotube films and compared their characteristics before and after they were hydrogen functionalized, using terahertz (THz) time-domain spectroscopy. Reduction of the power absorption of the samples was observed with hydrogen functionalization. To analyze the experimental results, the effective medium approximation (EMA) was adopted. Through the EMA, the effective plasma frequencies, damping rates, and other physical parameters located in the THz region were determined. In this way, decreases in the plasma frequencies and the damping rates were observed after hydrogen functionalization, which implies a decrease in the carrier density.