A new method to invert top-gate organic field-effect transistors for Kelvin probe investigations

摘要

In this contribution, we present a technique which allows for the investigation of the local channel potentials of a poly(3-hexylthiophene) (P3HT)-based top-gate field-effect transistor. Usually it is impossible to measure the channel potentials of a top-gate transistor with a Kelvin probe force microscope (KPFM) due to the electrical shielding of the top-gate or the weak capacitive coupling of the tip through the thick substrate to the channel. However, by depositing the entire device on a water solvable polyvinyl alcohol layer, devices can be completely detached from -the substrate, creating a free-standing functioning organic field-effect transistor (OFET). After detaching, it is possible to laminate the inverted device on another substrate. This method grants access to the usually hidden channel of the top-gate OFET, and therefore KPFM measurements can be performed.