The effect of interfacial roughness on the electrical properties of organic thin film transistors with an anisotropic dielectric layer

Abstract

We investigated anisotropic conduction effects of pentacene-based OTFT on an anisotropic insulator fabricated by obliquely evaporated silicon dioxide. As the evaporation angle of SiO2 increased, the anisotropic interaction at the dielectric interface and molecular ordering of evaporated pentacenes increased. However, in highly obliquely evaporated dielectric surface, it was observed that growth of the pentacene molecules was highly limited due to increased roughness at the inteface. The molecular ordering effect and the grain size effect depending on the surface anisotropy and the surface roughness were discussed with the results of the field-induced mobility and the surface morphology. We believe that further optimization of oblique evaporation in OTFTs would result in more anisotropic electrical property.