High-Frequency Sheet Conductance of Nanolayered WS 2 Crystals for Two-Dimensional Nanodevices
Time-resolved terahertz (THz) spectroscopy is a powerful technique for the determination of charge transport properties in photoexcited semiconductors. However, the relatively long wavelengths of THz radiation and the diffraction limit imposed by optical imaging systems reduce the applicability of THz spectroscopy to large samples with dimensions in the millimeter to centimeter range. Exploiting THz near-field spectroscopy, we present the first time-resolved THz measurements on a single exfoliated 2D nanolayered crystal of a transition metal dichalcogenide (WS2). The high spatial resolution of THz near-field spectroscopy enables mapping of the sheet conductance for an increasing number of atomic layers. The single-crystalline structuremore »