title: Liquid crystal-gated-organic field-effect transistors with in-plane drain-source-gate electrode structure.
abstract: We report planar liquid crystal-gated-organic field-effect transistors (LC-g-OFETs) with a simple in-plane drain-source-gate electrode structure, which can be cost-effectively prepared by typical photolithography/etching processes. The LC-g-OFET devices were fabricated by forming the LC layer (4-cyano-4'-pentylbiphenyl, 5CB) on top of the channel layer (poly(3-hexylthiophene), P3HT) that was spin-coated on the patterned indium-tin oxide (ITO)-coated glass substrates. The LC-g-OFET devices showed p-type transistor characteristics, while a current saturation behavior in the output curves was achieved for the 50-150 nm-thick P3HT (channel) layers. A prospective on/off ratio (>1 × 10(3)) was obtained regardless of the P3HT thickness, whereas the resulting hole mobility (0.5-1.1 cm(2)/(V s)) at a linear regime was dependent on the P3HT thickness. The tilted ordering of 5CB at the LC-P3HT interfaces, which is induced by the gate electric field, has been proposed as a core point of working mechanism for the present LC-g-OFETs.
authors.affiliation: Organic Nanoelectronics Laboratory, Department of Chemical Engineering, and ‡Research Institute of Advanced Energy Technology, Kyungpook National University , Daegu 702-701, Republic of Korea.
authors.forename: Jooyeok
authors.initials: J
authors.lastname: Seo
authors.forename: Sungho
authors.initials: S
authors.lastname: Nam
authors.forename: Jaehoon
authors.initials: J
authors.lastname: Jeong
authors.forename: Chulyeon
authors.initials: C
authors.lastname: Lee
authors.forename: Hwajeong
authors.initials: H
authors.lastname: Kim
authors.forename: Youngkyoo
authors.initials: Y
authors.lastname: Kim
mesh_terms: D003460:Crystallization; D025802:Electric Capacitance; D017097:Electric Impedance; D004566:Electrodes; D007204:Indium / Q000737:chemistry; D050866:Liquid Crystals; D008422:Materials Testing; D008853:Microscopy; D036103:Nanotechnology / Q000379:methods*; D009930:Organic Chemicals / Q000737:chemistry*; D012666:Semiconductors; D013696:Temperature; D017971:Tin Compounds / Q000737:chemistry; D014173:Transistors, Electronic
chemical_list: D009930:Organic Chemicals; D017971:Tin Compounds; D007204:Indium; C045358:stannic oxide
keywords: 5CB; LC-g-OFET; dipole; liquid crystal; organic transistor