Conference Program - LOPE-C 2011

SCIENTIFIC CONF. | WEDNESDAY-JUNE 29, 2011
Track 4
Organic Transistors (02:30 pm - 04:00 pm) | LOCATION HARMONIE D / LEVEL C2
02:30 pm Organic and hybrid thin?film transistors with novel architectures and high performance
Prof. Bernard Kippelen,
Georgia Institute of Technology, United States
Over the last decades, organic thin?film transistors (OTFTs) have made great progress. The field?effect mobility in OTFTs has improved to a level where organic
semiconductors compete with amorphous silicon (a?Si). However, an advantage with organic semiconductors is that the performance levels of n?channel and p?channel
devices are comparable which is important for the design of complementary circuits. Despite these advances in field?effect mobility, long?term environmental and
operational stabilities are still two major issues before OTFTs can be commercialize and realize their fll potential. In this talk we will discuss the performance of OTFTs
based on bi?layer gate dielectrics. In particular, we will report on devices fabricated from solution processed organic semiconductors with a top gate geometry. Such
devices show an average mobility value of 0.39±0.16 cm2/Vs and operate at voltages below 8 V. These devices do not show any significant degradation in mobility
nor change in threshold voltage after 20,000 multiple scans, after a 24 h constant dc bias stress, or after exposure to air for over seven months. We will also report on
hybrid organic?inorganic complementary inverters composed of pentacene and amorphous InGaZnO for p? and n? channel thin?film transistors (TFTs) fabricated on
flexible polyethersulfone substrates. We will describe a new co?planar channel geometry for the realization of such transistors and complementary inverters wherein n? and
p?type channels are horizontally distributed with different channel widths to achieve balanced operation. Using this geometry, we could demonstrate high performance
ambipolar?like transistors consisting of amorphous?InGaZnO (mobility of 10 cm2/Vs) and pentacene channels (mobility of 0.3 cm2/Vs) with performance parameters
comparable to those of unipolar transistors.
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