Polymer based solar cells and field effect transistors are rapidly emerging as realistic candidates in the global quest for alternative energy sources and low cost/energy efficient fabrication procedures. It is fundamentally critical to understand the origin and control of transport length scales in the active layer of these devices. We have recently introduced a method where the semiconducting polymer films when photoexcited with defined beam profiles generate excess charge carriers from the electronically excited state, which eventually spread over a volume exceeding the beam-sample cross-section. Interfacial barriers at the metal-semiconductor junction manifest in form of sizable contact resistance (CR) in polymer field effect transistors (PFET’s). We also demonstrate a method which is suitable for top contact PFETS to evaluate these barriers.
Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR)