Terahertz conductivity characterization of nanostructured graphene-like films for optoelectronic applications

Difficulty in deposition and integration of fragile graphene-like samples for optoelectronic devices may prevent a multiple contact measurement procedure.We employed noncontact and nondestructive transmission and reflection terahertz (THz)-pulsed spectroscopy to investigate not only the electrical conductivity, but also to study the optical properties of one-dimensional and two-dimensional graphene-like samples. The Drude and non-Drude models were applied to observe and compare the ultrafast carrier transport parameters and high mobility characteristic of such high conductance-nanostructured thin films without requirement for postprocess patterning. The diffusive coefficient and nanoscopic characteristic length from noncontact THz measurement enables us to predict the cut-off frequency of such devices in relevant optoelectronic applications in sub-THz and THz frequencies. The results show that the cut-off frequency of the devices increases with a reduction of the channel length.