Effect of dielectric behavior of gate dielectric polymers on memory characteristics of organic field-effect transistors

Abstract

Memory characteristics of organic field-effect transistors (OFETs) fabricated using poly(γ-methyl-L-glutamate) (PMLG) and poly(ε-benzyloxycarbonyl-L-lysine) [PLys(z)] as gate dielectrics are investigated. The origin of difference in the memory retention property in the transfer characteristics of the OFETs is investigated by thermally stimulated depolarized current (TSDC) and dielectric spectra measurements for the PLys(z) and PMLG films. TSDC measurements reveal that the depolarization of the PLys(z) film is mainly dominated by a single relaxation process around room temperature, but that of the PMLG film is not dominated by a relaxation process. Further, the PLys(z) film shows dielectric dispersion near room temperature, but the PMLG film does not show any dispersion. This causes difference in the electric characteristics of OFETs.