High Mobility, Stable, N-channel Organic Thin-Film Transistors
Speaker: Prof. Ian Hill, Dalhousie University, Halifax, Canada
Series: Topical Seminars
Location: Engineering Quadrangle B205
Date/Time: Monday, September 20, 2010, 4:00 p.m. - 5:00 p.m.
Abstract: Polycrystalline p-channel organic thin-film transistors with hole mobilities exceeding 1 cm2/Vs based on pentacene and its derivatives have been widely reported for more than a decade. This performance, while inferior to crystalline inorganic semiconductor-based transistors, is on par with those of amorphous silicon â the basis of the mutli-billion dollar active matrix liquid crystal display market.
Many of the envisioned applications for low-cost, large area organic electronics require not only p-channel but n-channel devices of comparable performance to be feasible, due to the greatly reduced power consumption of a complementary architecture (organic-CMOS). Recently, n-channel thin-film transistors based on N,Nâ²-ditridecyl-3,4,9,10-perylenetetracarboxylic diimide (PTCDI) derivatives have been fabricated with performance comparable to pentacene-based devices. Unfortunately, they have also demonstrated many undesirable characteristics, including large, unstable threshold voltages, on-off/off-on hysteresis, and poor air stability. I will report on our recent work to understand the origins of properties. Through systematic study and modification of the organic semiconductor/gate dielectric interface, we have been able to eliminate many of the undesirable properties of PTCDI-C13 transistors, and have demonstrated n-channel organic transistors with mobilities acceptable for organic-CMOS circuits with small, stable threshold voltages and virtually no hysteresis.