Brooks A. Jones

High-mobility bottom-contact n -channel organic transistors and their use in complementary ring oscillators

The electrical characteristics of bottom-contact organic field-effect transistors fabricated with the air-stable n-type semiconductor N,N′-bis(n-octyl)-dicyanoperylene-3,4:9,10-bis(dicarboximide) (PDI-8CN2) are described. The mobility, threshold voltage, subthreshold swing, and Ion∕Ioff ratio(VDS=40V, VG=0∼40V) are 0.14cm2∕Vs, 1.6V, 2.0V/decade, and 1.2×103, respectively. The effect of electrode/dielectric surface treatment on these devices is also examined, with a combination of 1-octadecanethiol and hexamethyldisilazane. Organic complementary five-stage ring oscillators were fabricated using pentacene and PDI-8CN2, and operated at an oscillation frequency of 34kHz and a propagation delay per stage of 3μs.

Nanoscale n-channel and ambipolar organic field-effect transistors

N-channel and ambipolar organic field-effect transistors (OFETs) with a few tens of nanometer channel length were fabricated and characterized. N,N′-bis(n-octyl)-dicyanoperylene-3,4:9,10-bis(dicarboximide) (PDI-8CN2) was employed as the active semiconductor and yielded a linear regime electron mobility of 2.3×10−3cm2∕Vs at 5×105V∕cm in an OFET with channel length of 15nm. An ambipolar heterostructure transistor consisting of thin layers of PDI-8CN2 and pentacene was fabricated with channel length of about 23nm. Field-effect hole and electron mobilities of 9.2×10−3 and 4.0×10−3cm2∕Vs, respectively, are obtained at 5×105V∕cm. These results represent the shortest channel length n-channel and ambipolar organic transistors that have been fabricated.

Organic-Inorganic Flexible and Transparent Electronics

In this investigation, synthetic and fabrication approaches to new organic, inorganic, and hybrid materials/devices for flexible/transparent electronic applications are presented. The covered topics are: 1. Utilization of new solution-processable dielectrics exhibiting ultra-high capacitance, low leakage, and high breakdown fields. 2. Development of new low-temperature and/or solution phase processes for thin-film deposition of optically transparent inorganic/hybrid semiconductors. 3. Rational design, realization, and understanding of new electrically-active high-mobility transparent n-type organic semiconductors. We demonstrate that the combinations of these materials sets allow the fabrication of transistors and electronic circuits excellent performance characteristics. In particular, we show several examples where transparent/flexible transistors and circuits are achieved exhibiting excellent performance.

Organic complementary circuits using solution deposited active semiconductors

Byungwook Yoo a, Debarshi Basu a, Taeho Jung a, Daniel Fine a, Brooks A. Jones b, Antonio Facchetti b Michael R. Wasielewski b, Tobin J. Marks b, Klaus Dimmler c, and Ananth Dodabalapur a a Department ofElectrical and Computer Engineering, Microelectronics Research Center, The University ofTexas at Austin, 10100 Burnet Rd, Bldg 160, Austin, TX 78758, email: bwyoo(dmail. utexas. edu, ph: 1-512-232-1846 b Department of Chemistry, the Materials Research Center, and the Centerfor Nanofabrication & Molecular SelfAssembly, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208-3113 cOrganicID, 422 East Vermio Ave, Colorado Springs, CO 80903