Probing Coulomb Interactions on Charge Transport in Few‐Layer Organic Crystalline Semiconductors by the Gated van der Pauw Method

Abstract

AbstractA general understanding of the nature of the charge motions at the organic/dielectric interface requires an accurate examination on the influence from the Coulomb interactions among carriers. However, difficulties on this substantial issue are due to complicated interpretation and extraction of the intrinsic electrical parameters for the organic films. Here, the carrier transport in highly ordered, few‐layer organic crystalline semiconductors is studied by a geometry‐independent gated van der Pauw method, confining the charge carrier distribution at the precision of molecular layers and minimizing the effects of extrinsic factors. The characteristics of carrier transport are varied in different film layers and show nonideal features. The Fröhlich polaron model well explains the features and suggests that the Coulomb interactions among carriers should be considered at a high carrier density, which is manifested by the characteristic parameter 〈ξ 〉/2 measuring the extra potential for polaron transport. This understanding of the physical process between Coulomb interactions and polaron transport in organic crystalline semiconductors can enable promising strategies for achieving more ideal transistor performance and new device physics.