• Journal of the Semiconductor & Display Technology
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• v.5 no.1 s.14
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• pp.21-25
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• 2006

To improve the performance of organic thin film transistor, we investigated the properties of gate insulator's surface according to the leakage current by I-V measurement. The surface was treated by the dilute n-octadecyltrichlorosilane solution. The alkyl group of n-octadecyltrichlorosilane induced the electron tunneling and the electron tunneling current caused the breakdown at high electric field, consequently shifting the breakdown voltage. The 0.5% sample with an electron-rich group was found to have a large leakage current and a low barrier height because of the effect of an energy barrier lowered by, thermionic current, which is called the Schottky contact. The surface properties of the insulator were analyzed by I-V measurement using the effect of Poole-Frankel emission.

• 전기의세계
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• v.20 no.3
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• pp.27-31
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• 1971

The main focus of this paper is on the study of the radiation effect upon the electrical property of a A-Kind insulator which is one of the organic insulators. The varnished cloth is so typical of the A-Kind insulators as to be selected for a sample. AC and Impluse voltage is applied to the variable Gamma ray irradiated dose samples with the constant time duration and the dielectric breakdown voltage are measured from the sample. The experimental data of the dielectric breakdown voltage are considerably decreased. The above conclusion is useful for the selection and application of the orgainc insulators under the irradiation effects.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.1
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• pp.93-98
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• 2013

In this paper, We have fabricated PMMA thin films by plasma polymerization method for organic thin film transistor's insulator layer. For improving the characteristics of organic transistor, we tested transistor's mobility and output values with organic transistor's electrode structures. As a results, the mobility of top contact was $8{\times}10^{-3}[cm^2V^{-1}s^{-1}]$, that of bottom contact was $2{\times}10^{-4}[cm^2V^{-1}s^{-1}]$. Also, off current of bottom contact was increased. Therefore, we recommend the top contact electrode structure of organic transistor.

• Transactions on Electrical and Electronic Materials
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• v.8 no.1
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• pp.36-40
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• 2007

Inorganic layers, such as SiOxNy and SiOx deposited using plasma sublimation method, were tested as passivation layer for organic thin-film-transistors (OTFTs). OTFTs with bottom-gate and bottom-contact structure were fabricated using pentacene as organic semiconductor and an organic gate insulator. SiOxNy layer gave little change in characteristics of OTFTs, but SiOx layer degraded the performance of OTFTs severely. Inferior barrier properties related to its lower film density, higher water vapor transmission rate (WVTR) and damage due to process environment of oxygen of SiOx film could explain these results. Polyurea and polyvinyl acetates (PVA) were tested as organic passivation layers also. PVA showed good properties as a buffer layer to reduce the damage come from the vacuum deposition process of upper passivation layers. From these results, a multilayer structure with upper SiOxNy film and lower PVA film is expected to be a superior passivation layer for OTFTs.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.2
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• pp.21-25
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• 2009

The organic-inorganic thin film transistors (OITFTs) with ZnO channel layer and the cross-linked PVP (Poly-4-vinylphenol) gate insulator were fabricated on the patterned ITO gate/glass substrate. ZnO channel layer was deposited by using atomic layer deposition (ALD). In order to improve the electrical properties, $O_2$ plasma treatment onto PVP film was introduced and investigated the effect of the plasma treatments on the electrical properties of the OITFTs. The field effect mobility and sub-threshold slope (SS) values of the OITFT decreased slightly from 0.24 to 0.16 $cm^2/V{\cdot}s$ and from 9.7 to 9.2 V/dec, respectively with increasing RF power from 30 to 50 Watt. The $I_{on/off}$ ratio was about $10^3$ for all samples with $O_2$ plasma treatment.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.142.2-142.2
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• 2016

The metal intercalation to an organic semiconductor is of importance since the charge transfer between a metal and an organic semiconductor can induce the highly enhanced conductivity for achieving efficient organic electronic devices. In this regard, the changes of the electronic structure of copper phthalocyanine (CuPc) caused by the intercalation of potassium are studied by ultraviolet photoemission spectroscopy (UPS) and density functional theory (DFT) calculations. Potassium intercalation leads to the appearance of an intercalation-induced peak between the highest molecular occupied orbital (HOMO) and the lowest molecular unoccupied orbital (LUMO) in the valence-band spectra obtained using UPS. The DFT calculations show that the new gap state is attributed to filling the LUMO+1, unlike a common belief of filling the LUMO. However, the LUMO+1 is not conductive because the ${\pi}$-conjugated macrocyclic isoindole rings on the molecule do not make a contribution to the LUMO+1. This is the origin of a metal-insulator transition through heavily potassium doped CuPc.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.356-358
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• 2004

In this paper we fabricated and succeeded to demonstrate a test panel for AMOLED on 2" glass and PET substrate. The test panel consisted of an array of 64 x 64 pixels in which OLEDs was driven by pentacene TFT. OTFTs were made of the inverted staggered structure and employed polyvinylphenol as the gate insulator and pentacene thin film as the active layer, producing the filed effect mobility of 0.3$cm^2$/V.sec and on/off current ratio of $10^5$. OLEDs were composed of TPD for HTL and Alq3 for EML with 35nm thick each, generating green monochrome light.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05a
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• pp.57-60
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• 2001

The characterization of organic Metal/Insulator/Metal(MIM) devices were investigated from LB films. The physicochemical properties of the LB films were by UV absorption spectrum and AFM. We give pressure stimulation into organic thin films and then manufacture a device under the accumulation condition that the state surface pressure is 2, 10, 30[mN/ml The stable images are probably due to a strong interaction between the monolayer film and glass substrate. We are unable to obtain molecule resolution in images of the films but did see a marked contrast between images of the bare substrate and those with the network structure film deposited onto it.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1590-1592
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• 2002

In this work the electrical characteristics of organic TFTs using organic insulator and flexible polyester substrate have been investigated. Pentacene and PVP(polyvinylphenol) are used as an active semiconducting layer and dielectric layer respectively. Pentacene was thermally evaporated in vacuum at a pressure of about $1{\times}10^{-6}$ Torr and at a deposition rate of $0.5{\AA}$/sec, and PVP was spin-coated. Aluminium and gold were used for gate and source/drain electrodes. 0.1mm thick flexible polyester substrate was used instead of glass or silicon wafer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.187-190
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• 1996

Conducting polymers have band structures similar to those of inorganic semiconductors such as silicon. Several electronic devices have been constructed with conjugated polymers, mainly Schottky diodes and Metal-Insulator-Semiconductor Field-Effect Transistors (MISFET's). Organic semiconductor has been reported as active materials in MISFET's.$^{1.4}$ In our laboratory, $\alpha$-Sexithiencyl ($\alpha$-6T) has been synthesized and purified by sublimation method. In this study, thin films of $\alpha$-Sexithienyl were prepared on various substrates in ultra-high vacuum chamber by vacuum evaporation method, so called OMBD(Organic Molocular Beam Deposition).$^{7.9}$ The $\alpha$-Sexithienyl thin films were deposited with various deposition conditions. The crystalline structure, and molecular orientation of these films have being studied by using UV/Vis. spectroscopy and X-Ray Diffractometry.