• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.307-309
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• 2009

We have fabricated vertical-type organic transistors (static induction transistors; SITs) with built-in nano-triode arrays formed in parallel by a colloidal-lithography technique. Using this technique, we could fabricate a microstructure in a lateral direction within a large-scale organic device without relying on photolithography. The organic transistor showed low operating voltages, high current output, and large transconductance.

• Macromolecular Research
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• v.17 no.9
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• pp.646-650
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• 2009

We report the fabrication of pentacene organic field-effect transistors (OFETs) using a fluorinated styrene-alt-maleic anhydride copolymer gate dielectric, which was prepared from styrene derivatives with a fluorinated side chain [$-CH_2-O-(CH_2)_2-(CF_2)_5CF_3$] and maleic anhydride through a solution polymerization technique. The fluorinated side chain was used to impart hydrophobicity to the surface of the gate dielectric and maleic anhydride was employed to improve its wetting properties. A field-effect mobility of 0.12 cm$^2$/Vs was obtained from the as-prepared top-contact pentacene FETs. Since various functional groups can be introduced into the copolymer due to the nature of maleic anhydride, its physical properties can be manipulated easily. Using this type of copolymer, the performance of organic FETs can be enhanced through optimization of the interfacial properties between the gate dielectric and organic semiconductor.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.72-72
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• 2012

The next generation electronics need to not only be smaller but also be more flexible. To meet such demands, electronic devices using two dimensional (2D) atomic crystals have been studied intensely. Especially, graphene which have unprecedented performance fulfillments in versatile research fields leads a parade of 2D atomic crystals. In this talk, I will introduce the electrical characterization and applications of graphene for prominently electrical transistors realization. Even the rising 2D atomic crystals such as hexagonal boron nitride (h-BN), molybdenum disulfide (MoS2) and organic thin film for field effect transistor (FET) toward competent enhancement will be mentioned.

• Journal of the Korean Applied Science and Technology
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• v.19 no.4
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• pp.335-338
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• 2002

A new process for polymeric gate insulator in field-effect transistors was proposed. Fourier transform infrared absorption spectra were measured in order to identify ODPA-ODA polyimide. Its breakdown field and electrical conductivity were measured. All-organic thin-film transistors with a stacked-inverted top-contact structure were fabricated to demonstrate that thermally evaporated polyimide films could be used as a gate insulator. As a result, the transistor performances with evaporated polyimide was similar with spin-coated polyimide. It seems that the mass-productive in-situ solution-free processes for all-organic thin-film transistors are possible by using the proposed method without vacuum breaking.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1319-1321
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• 2009

Copper phthalocyanine (CuPc) Field-effect transistors (FETs) was successfully fabricated on plastic substrates. Orientation of CuPc crystallites on substrate could be obtained via rubbing process. It was revealed that CuPc crystallites were perpendicularly aligned on PES substrates with the rubbing direction. The performance of FETs was affected by orientation of CuPc on rubbed substrates.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.69-70
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• 2000

There are currently considerable interest in the applications of conjugated polymers, oligomers, and small molecules for thin-film electronic devices. Organic materials have potential advantages to be utilized as semiconductors in field-effect transistors and light-emitting diodes. In this study, pentacene thin-film transistors (TFTs) were fabricated on glass substrate. Aluminums were used for gate electrodes. Silicon dioxide was deposited as a gate insulator by PECVD and patterned by reactive ion etching (R.I.E). Gold was used for the electrodes of source and drain. The active semiconductor pentacene layer was thermally evaporated in vacuum at a pressure of about $10^{-8}$ Torr and a deposition rate $0.3{\AA}/s$. The fabricated devices exhibited the field-effect mobility as large as 0.07 $cm^2/V.s$ and on/off current ratio as larger than $10^7$.

• Bulletin of the Korean Chemical Society
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• v.33 no.4
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• pp.1128-1134
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• 2012

We investigated a new method for patterning organic field-effect transistors (OFETs) using a photopatternable conducting polymer nanocomposite, consisting of poly(3-hexylthiophene) (P3HT)-coated gold nanoparticles (AuNPs) that had been modified with a photoreactive cinnamate group, to form P3HT-AuNP-CI. We found that the addition of the cinnamate group to the nanoparticle surface assisted the preparation of a solvent-resistive semiconducting film and preserved the P3HT ordering, which was interrupted by Au-P3HT interactions, as well as provided UV-controllable electrical properties. The P3HT-AuNPs-CI films could be microscale-patterned via a UV crosslinking photoreaction, represented as a promising photopatternable semiconductor material for use in advanced applications, with tunable electrical properties for fabrication of sub-micron and microscale electronic devices.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.717-720
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• 2002

In this work, the electrical characteristics of organic thin film transistors with the surface-treated organic gate insulators have been studied. For the surface treatment, the simple rubbing technique was used. The field effect mobilities of the devices with PVP gate insulator was improved about four times as high as those of TFTs without the insulator surface treatment.

• Journal of Adhesion and Interface
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• v.22 no.3
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• pp.91-97
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• 2021

By introducing an organic interlayer on the Parylene C dielectric surface, the electrical device performances and the operating stabilities of organic field-effect transistors (OFETs) were improved. To achieve this goal, hexamethyldisilazane (HMDS) and octadecyltrichlorosilane (ODTS), as the organic interlayer materials, were used to control the surface energy of the Parylene C dielectrics. For the bare case used with the pristine Parylene C dielectrics, the field-effect mobility (μ_FET) and threshold voltage (V_th) of dinaphtho[2,3-b:2',3'-f ]thieno[3,2-b]- thiophene (DNTT) FET devices were measured at 0.12 cm²V^-1s^-1 and - 5.23 V, respectively. On the other hand, the OFET devices with HMDS- and ODTS-modified cases showed the improved μ_FET values of 0.32 and 0.34 cm²V^-1s^-1, respectively. More important point is that the μ_FET and V_th of the DNTT FET device with the ODTS-modified Parylene C dielectric presented the smallest changes during a repeated measurement of 1000 times, implying that it has the most stable operating stability. The results could be meaned that the organic interlayer, especially ODTS, effectively covers the Parylene C dielectric surface with alkyl chains and reduces the charge trapping at the interface region between active layer and dielectric, thereby improving the electrical operating stability.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.147-148
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• 2005

We report on high-performance organic field-effect transistors by promoting surface-mediated two-dimensional molecular ordering in organic semiconductor. To achieve this goal, we have controlled the intermolecular interaction at the interface between organic semiconductor and the insulator substrate.