title: Study of surface-modified PVP gate dielectric in organic thin film transistors with the nano-particle silver ink source/drain electrode.
abstract: We have fabricated the flexible pentacene based organic thin film transistors (OTFTs) with formulated poly[4-vinylphenol] (PVP) gate dielectrics treated by CF4/O2 plasma on poly[ethersulfones] (PES) substrate. The solution of gate dielectrics is made by adding methylated poly[melamine-co-formaldehyde] (MMF) to PVP. The PVP gate dielectric layer was cross linked at 90 degrees under UV ozone exposure. Source/drain electrodes are formed by micro contact printing (MCP) method using nano particle silver ink for the purposes of low cost and high throughput. The optimized OTFT shows the device performance with field effect mobility of the 0.88 cm2/V s, subthreshold slope of 2.2 V/decade, and on/off current ratios of 1.8 x 10(-6) at -40 V gate bias. We found that hydrophobic PVP gate dielectric surface can influence on the initial film morphologies of pentacene making dense, which is more important for high performance OTFTs than large grain size. Moreover, hydrophobic gate dielelctric surface reduces voids and -OH groups that interrupt the carrier transport in OTFTs.
authors: Department of Electronics Engineering, Chungnam National University, Daejeon 305-764, Korea.
authors: Ho-Jin
authors: HJ
authors: Yun
authors: Yong-Hyun
authors: YH
authors: Ham
authors: Hong-Sik
authors: HS
authors: Shin
authors: Kwang-Seok
authors: KS
authors: Jeong
authors: Jeong-Gyu
authors: JG
authors: Park
authors: Deuk-Sung
authors: DS
authors: Choi
authors: Ga-Won
authors: GW
authors: Lee