High-Resolution ac Measurements of the Hall Effect in Organic Field-Effect Transistors

The Hall effect would be a powerful probe for studying delocalized (bandlike) transport in semiconductors, because localized carriers do not contribute significantly to the effect. Unfortunately, the Hall voltage is typically very small in organic semiconductors. The authors develop a technique for high-resolution measurements of this effect in organic field-effect transistors (OFETs), utilizing a small ac magnetic field ($<$0.25 T). This method extends studies of intrinsic charge transport to systems with very low carrier mobilities, providing a significant step forward that should improve the design and optimization of OFETs, and other devices.