The organic FET with poly(peptide) derivatives and poly(methyl-methacrylate) gate dielectric

The field effect transistor (FET) was fabricated with pentacene as an active layer and polymer insulator as a gate dielectric. Poly(γ-methyl-L-glutamate) [PMLG] and poly(methyl-methacrylate) [PMMA] were used as one of the polymeric gate dielectric. PMLG has the large dipole moment along the rod-like main chain and the small dipole moment in the side chain. The effect of the main chain dipole and/or the side chain dipole on the FET was compared with that of PMMA gate dielectric, which has dipole moment only at side chain. When PMLG gate dielectric was used, the hysteresis in the transfer characteristics was considerably increased as compared with that in the case of other polymeric gate dielectrics. It is considered that the large hysteresis behavior is taken place by both the dipole moments of the side chain and the main chain.