Overview
Project 01
Project 02
Project 04
Project 06
Project 07
Project 08
Project 10
Project 11
Project 12
Project 13
Project 14

Project 12 – Functionalised Gate Dielectrics for Organic Field Effect Devices

Siegfried Bauer, Univ.Prof.Dr.

The project aims to investigate organic dielectric materials in conjunction with organic field effect transistors (OFETS) and solar cells in order to create functional devices. Examples include nonvolatile memory elements, pressure sensors and organic actuators driven by organic electronics, as well as MIS solar cells. Dielectric materials with tailored functionalities are considered: charge electrets with a long-term charge storage capability, ferroelectrets with a quasi-permanent “polarization”, amorphous dipole electrets with a frozen polarization, ferroelectric polymers with spontaneous polarization in the ferroelectric crystallographic phase, and relaxor ferroelectric polymers with a high dielectric constant. These features of the dielectrics also result in useful transducer properties, like piezoelectricity. Special emphasis will be given to the analysis of nonuniform electric field distributions in the dielectric and organic semiconductor films. Such nonuniform field distributions strongly influence the device performance, resulting for example in threshold shifts and hysteresis in OFETS and performance enhancement in solar cells. The nonuniform electric field distributions will be probed by employing thermal-wave probing techniques and by measuring the unusual electromechanical strain in such materials with a two-beam Nomarski interferometer. Thereby an optimization of the device performance will be achieved, an example is the maximizing of the bistability in nonvolatile memory elements.