Far-infrared conductivity of CuS nanoparticles measured by terahertz time-domain spectroscopy

This paper reports that terahertz time-domainspectroscopy is used to measure the optical properties of CuSnanoparticles in composite samples. The complex conductivity ofpure CuS nanoparticles is extracted by applying the Bruggeman effectivemedium theory. The experimental data are consistent with theDrude--Smith model of conductivity in the range of 0.2--1.5~THz. Theresults demonstrate that carriers become localized with abackscattering behaviour in small-size nanostructures. In addition,the time constant for the carrier scattering is obtained and is only64.3~{fs} due to increased electron interaction with interfaces andgrain boundaries.