We present a new technique to determine the carrier mobility $\mu$ in semiconducting, undoped, conjugated polymers in the millimeter-wave frequency range, 10–500 GHz. This method probes charge conduction on mesoscopic length scales, a regime inaccessible to other transport experiments. The experiment is based on the detection of millimeter-wave absorption of field-induced charge in polymer diodes, and is applied to poly( $p$-phenylene vinylene). We demonstrate that locally $\mu$ can be as high as ${10}^{-4\mathrm{}}{m}^2/\mathrm{V}\mathrm{s}$, and deduce the typical hopping parameters in the mesoscopic high- $\mu$ regions in the material.

• Received 18 December 2000

DOI:https://doi.org/10.1103/PhysRevLett.87.086601