title: Improved morphology and performance from surface treatments of naphthalenetetracarboxylic diimide bottom contact field-effect transistors.
abstract: We report bottom contact organic field-effect transistors (OFETs) with various surface treatments based on n-channel materials, specifically, 1,4,5,8-naphthalene-teracarboxylic diimides (NTCDIs) with three different fluorinated N-substituents, systematically studied with a particular emphasis on the interplay between the morphology of the organic semiconductor films and the electrical device properties. The morphological origins of the improvements were directly and dramatically visualized at the semiconductor-contact interface. As a result of a series of treatments, a large range of performances of bottom contact side-chain-fluorinated NTCDI OFETs (mobility from 1 x 10(-6) to 8 x 10(-2) cm(2)/(V s), on/off ratio from 1 x 10(2) to 1 x 10(5)) were obtained. The surface treatments enabled systems that had shown essentially no OFET activity without electrode modification activity to perform nearly as well as top contact devices made from the same materials. In addition, for the fresh bottom contact NTCDI device, the effect of gate bias stress on the tens-of-minutes time scale, during which the threshold voltage (V(t)) shifted and relaxed with similar time constants, was observed.
authors.affiliation: Department of Materials Science and Engineering, Johns Hopkins University, 103 Maryland Hall, 3400 North Charles Street, Baltimore, Maryland 21218, USA.
authors.forename: Jia
authors.initials: J
authors.lastname: Sun
authors.forename: Rod
authors.initials: R
authors.lastname: Devine
authors.forename: Bal M
authors.initials: BM
authors.lastname: Dhar
authors.forename: Byung Jun
authors.initials: BJ
authors.lastname: Jung
authors.forename: Kevin C
authors.initials: KC
authors.lastname: See
authors.forename: Howard E
authors.initials: HE
authors.lastname: Katz