Atomic polarization and local reactivity on organic ferroelectric surfaces: Engineering fluoropolymer films for ferroelectric nanolithography

Atomic polarization of the organic ferroelectric material polyvinylidene fluoride (PVDF) can be manipulated at the nanometer scale in order to influence the local electronic structure and chemical reactivity at the surface. A DC voltage applied through a conductive scanning probe tip is used to pattern ferroelectric domains in a PVDF thin film, and the polarization direction of these domains influences the kinetics of electron exchange at the surface. By means of a surface photoreduction reaction, which occurs in a metal ion solution under ultraviolet irradiation, metal nanoparticles can be deposited in a predetermined configuration on the polymer surface. In addition to demonstrating the ferroelectric nanolithography process on a novel organic substrate, this study serves to determine the character of the electronic transport, whether the observed photoconductivity is a bulk material effect or the result of the PVDF/electrode interface. The influence of ultraviolet light on the material is discussed in terms of its effect on the electronic properties, specifically its interaction with defect states present within the material. It was determined that these defect states are responsible for the observed photoconductivity in PVDF and the driving force for the domain specific photoreduction reaction utilized in the ferroelectric nanolithography process