title: Universal diffusion-limited injection and the hook effect in organic thin-film transistors.
abstract: The general form of interfacial contact resistance was derived for organic thin-film transistors (OTFTs) covering various injection mechanisms. Devices with a broad range of materials for contacts, semiconductors, and dielectrics were investigated and the charge injections in staggered OTFTs was found to universally follow the proposed form in the diffusion-limited case, which is signified by the mobility-dependent injection at the metal-semiconductor interfaces. Hence, real ohmic contact can hardly ever be achieved in OTFTs with low carrier concentrations and mobility, and the injection mechanisms include thermionic emission, diffusion, and surface recombination. The non-ohmic injection in OTFTs is manifested by the generally observed hook shape of the output conductance as a function of the drain field. The combined theoretical and experimental results show that interfacial contact resistance generally decreases with carrier mobility, and the injection current is probably determined by the surface recombination rate, which can be promoted by bulk-doping, contact modifications with charge injection layers and dopant layers, and dielectric engineering with high-k dielectric materials.
authors.affiliation: State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, SYSU-CMU Shunde International Joint Research Institute, School of Electronics and Information Engineering, Sun Yat-sen University, Guangzhou 510275, People's Republic of China.
authors.forename: Chuan
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Energy and Materials Engineering, Dongguk University, 30 Pildong-ro, 1 gil, Jung-gu, Seoul 04620, Republic of Korea.
authors.forename: Gunel
authors.initials: G
authors.lastname: Huseynova
authors.affiliation: Department of Energy and Materials Engineering, Dongguk University, 30 Pildong-ro, 1 gil, Jung-gu, Seoul 04620, Republic of Korea.
authors.forename: Yong
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Energy and Materials Engineering, Dongguk University, 30 Pildong-ro, 1 gil, Jung-gu, Seoul 04620, Republic of Korea.
authors.forename: Dang Xuan
authors.initials: DX
authors.lastname: Long
authors.affiliation: Department of Energy and Materials Engineering, Dongguk University, 30 Pildong-ro, 1 gil, Jung-gu, Seoul 04620, Republic of Korea.
authors.forename: Won-Tae
authors.initials: WT
authors.lastname: Park
authors.affiliation: International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: Xuying
authors.initials: X
authors.lastname: Liu
authors.affiliation: International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Minari
authors.affiliation: Department of Energy and Materials Engineering, Dongguk University, 30 Pildong-ro, 1 gil, Jung-gu, Seoul 04620, Republic of Korea.
authors.forename: Yong-Young
authors.initials: YY
authors.lastname: Noh