• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.543-544
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• 2006

Pentacene thin film transistors fabricated without photolithographic patterning were fabricated on the plastic substrates. Both the organic/inorganic thin films and metallic electrode were patterned by shifting the position of the shadow mask which accompanies the substrate throughout the deposition process. By using an optically transparent zirconium oxide ($ZrO_2$) as a gate insulator and octadecyltrimethoxysilane (OTMS) as an organic molecule for self-assembled monolayer (SAM) to increase the adhesion between the plastic substrate and gate insulator and the mobility with surface treatment, high-performance transistor with field effect mobility $.66\;cm^2$/V s and $I_{on}/I_{off}$>$10^5$ was formed on the plastic substrate. This technique will be applicable to all structure deposited at low temperature and suitable for an easy process for flexible display.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.60-63
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• 2009

In this letter we report on the carrier velocity of polycrystalline pentacene transistors as a function of electric field. We performed a series of measurements on devices with a range of channel lengths. At moderate electric fields (<$5{\times}10^5$ V/cm), the characteristics are similar to those of disordered or amorphous organic semiconductors. The highest velocities we have measured are near $6{\times}10^4$ cm/s at room temperature. We perform quasi-static and dynamic measurements to measure carrier velocity. These results fill an important void between experimental results that have been obtained with disordered/amorphous organic semiconductors and single crystals.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.568-570
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• 2009

Octadecyltrichlorosilane (OTS) self-assembled monolayer was selectively patterned by deep ultraviolet exposure, resulting in differential surface state, hydrophilic area with OTS hydrophobic surroundings. High-resolution (<10 ${\mu}m$) nanoparticulate Ag electrodes and organic semiconductors were patterned from simple dip-casting and ink-jetting on the pre-patterned hydrophilic surface, forming all solution-processed organic thin film transistors. The devices typically have shown a mobility of 0.065 $cm^2/V{\cdot}s$ and on-off current ratio of $8{\times}10^5$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1754-1756
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• 2000

Organic semiconductors based on fused-ring polycyclic aromatic hydrocarbon have great potential to be utilized as an active layer for electronic and optoelectronic devices. In this study, pentacene thin films and electrode materials were deposited by Organic Molecular Beam Deposition(OMBD) and vacuum evaporation respectively. For the gate dielectric, polyamic acid was spin-coated and cured into polyimide at 350$^{\circ}C$. Electrical characteristics of the devices were investigated, where the channel length and width was 50${\mu}m$ and 5mm. It was found that field effect mobility was 0.012$cm^{2}/Vs$, and on/off current ratio was $10^5$.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.261.1-261.1
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• 2013

Well-aligned nanowire arrays can be used as building blocks for nanoscale device. Recently, we reported that well-aligned single-crystal organic nanowires has been created by using a direct printing method which is named liquid-bridge mediated nanotransfer molding (LB-nTM). Moreover, multi-layering nanostructures can be fabricated by repeating this printing process. As a result, it is possible to make simple and basic concept of heterojunction devices such as crossed nanowire devices. We fabricated crossed single-crystal organic nanowires nanojunction devices from 6,13-bis (triisopropylsilylethynyl) pentacene (TIPS-PEN) and fullerene (C60) single-crystal nanowires using by direct printing method in solution process. Crossed TIPSPEN/ C60 single-crystal nanowires diode has rectifying behavior with on/off ratios of ~13. In addition, the device shows photodiode characteristics as well as rectification. Our study represent methodology of heterojunction devices using single-crystal nanowires, thereby provide a new direction of future nanoelectronics.

• Transactions on Electrical and Electronic Materials
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• 제8권1호
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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.

• 한국전기전자재료학회논문지
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• 제19권6호
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• pp.563-567
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• 2006

Indium tin oxide (ITO) used as an electrode in organic light emitting diodes (OLEDs) and organic thin film transistors (OTFTs) was modified by a self-assembled monolayer (SAM). For device fabrication, surface of the ITO was modified by immersion in a solution including various phosphonic acid at room temperature in order to increase work function of an electrode. The work function of ITO with SAM was measured by Kelvin probe. Work function increase of 0.88 eV was observed in ITO with various SAM. Therefore, ohmic contact is achieved in an interface between ITO and organic semiconductors (pentacene). We analyzed the origin of work function increase of ITO with SAM by X-ray photoelectron spectroscopy. We confirmed that increase of oxygen bonding energy attributed to increase the work function of ITO. These results suggested that ITO with the SAM gives a high possibility for high performance of OLEDS and OTFTs.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1178-1181
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• 2006

We fabricated a flexible OTFT(organic thin film transistor) backplane for the electrophoretic display. The backplane was composed of $128{\times}96pixels$ on the Polyethylene Naphthalate substrate in which each pixel had one OTFT. The OTFTs employed bottom contact structure and used the cross-linked polyvinylphenol for gate insulator and pentacene for active layer

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.1081-1084
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• 2003

본 논문에서는 OPVD시스템을 이용하여 펜타센 박막을 형성하였고 소자제작을 통해 그 특성을 평가 하였다. OPVD시스템을 이용하여 제작된 OTFT의 이동도는 0.01㎠/V·sec로써 기존의 OMBD로 제작된 OTFT보다 약 10배 정도 향상된 값을 나타냈으며, SS는 2.5Ion/off ratio 는 10⁴, 누설전류는 100pA 였다. 이러한 OPVD시스템에 의한 방법은 대면적 성막이 가능할 뿐 만 아니라 형성된 박막의 결정도 또한 기존의 OMBD방법으로 형성된 박막보다 월등하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.668-672
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• 2003

In order to reach the high electrical quality of organic thin film transistors (OTFTs) such as high mobility and on-off current ratio, it is strongly desirable to study the enhancement of electrical properties in OTFTs. Here, we report the novel method of hydrogen $(H_{2})$ plasma treatment to improve electrical properties in inverted staggered OTFTs based on pentacene as active layer. To certify the effect of this method, we compared the electrical properties of normal device as a reference with those of device using the novel method. In result, the normal device as a reference making no use of this method exhibited a field effect mobility of 0.055 $cm^{2}/Vs$, on/off current ratio of $10^{3}$, threshold voltage of -4.5 V, and subthreshold slope of 7.6 V/dec. While the device using the novel method exhibited a field effect mobility of 0.174 $cm^{2}/Vs$, on/off current ratio of $10^{6}$. threshold voltage of -0.5 V, and subthreshold slope of 1.49 V/dec. According to these results, we have found the electrical performances in inverted staggered pentacene TFT owing to this novel method are remarkably enhanced. So, this method plays a key role in highly improving the electric performance of OTFTs. Moreover, this method is the first time yet reported for any OTFTs