title: Effect of the phase states of self-assembled monolayers on pentacene growth and thin-film transistor characteristics.
abstract: To investigate the effects of the phase state (ordered or disordered) of self-assembled monolayers (SAMs) on the growth mode of pentacene films and the performance of organic thin-film transistors (OTFTs), we deposited pentacene molecules on SAMs of octadecyltrichlorosilane (ODTS) with different alkyl-chain orientations at various substrate temperatures (30, 60, and 90 degrees C). We found that the SAM phase state played an important role in both cases. Pentacene films grown on relatively highly ordered SAMs were found to have a higher crystallinity and a better interconnectivity between the pentacene domains, which directly serves to enhance the field-effect mobility, than those grown on disordered SAMs. Furthermore, the differences in crystallinity and field-effect mobility between pentacene films grown on ordered and disordered substrates increased with increasing substrate temperature. These results can be possibly explained by (1) a quasi-epitaxy growth of the pentacene film on the ordered ODTS monolayer and (2) the temperature-dependent alkyl chain mobility of the ODTS monolayers.
authors.affiliation: Department of Chemical Engineering/Polymer Research Institute, Pohang University of Science and Technology, Pohang, 790-784, Korea.
authors.forename: Hwa Sung
authors.initials: HS
authors.lastname: Lee
authors.forename: Do Hwan
authors.initials: DH
authors.lastname: Kim
authors.forename: Jeong Ho
authors.initials: JH
authors.lastname: Cho
authors.forename: Minkyu
authors.initials: M
authors.lastname: Hwang
authors.forename: Yunseok
authors.initials: Y
authors.lastname: Jang
authors.forename: Kilwon
authors.initials: K
authors.lastname: Cho