Polarization effects in the channel of an organic field-effect transistor

Abstract

We present the results of our calculation of the effects of dynamical coupling of a charge-carrier to the electronic polarization and the field-induced lattice displacements at the gate-interface of an organic field-effect transistor (OFET). We find that these interactions reduce the effective bandwidth of the charge-carrier in the quasi-two dimensional channel of a pentacene transistor by a factor of two from its bulk value when the gate is a high-permittivity dielectric such as $({\text{Ta}}_2{\text{O}}_5)$ while this reduction essentially vanishes using a polymer gate-insulator. These results demonstrate that carrier mass renormalization triggers the dielectric effects on the mobility reported recently in OFETs.

19 pages, 3 figures