• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.170-170
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• 2006

[ ${\pi}-conjugated$ ] organic and polymeric semiconductors are receiving considerable attention because of their suitability as an active layer for electronic devices. An organic inverter with a full swing and a high gain can be obtained through the good qualities of the transfer characteristics of organic thin-film transistors (OTFTs); for example, a low leakage current, a threshold voltage ($V_{th}$) close to 0 V, and a low sub-threshold swing. One of the most critical problems with traditional organic inverters is the high operating voltage, which is often greater than 20 V. The high operating voltage may result in not only high power consumption but also device instabilities such as hysteresis and a shift of $V_{th}$ during operation. In this paper, low-voltage and little-hysteresis pentacene OTFTs and inverters in conjunction with PEALD $Al_{2}O_{3}\;and\;ZrO_{2}$ as the gate dielectrics are demonstrated and the relationships between the transfer characteristics of OTFT and the voltage transfer characteristics (VTCs) of inverter are investigated.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.194-197
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• 2006

One novel electrode-architecture has been adapted to fabricate transparent OTFTs. The device has more than 70% transmittance, yet reminds high performance. Furthermore, we also use transfer line method to prove that the device performance enhancement indeed contributes from the reduction of the contact resistances. It is anticipated that the transparent OTFTs would be very suitable to be the driving circuits for liquid crystal displays (LCDs).

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.314-316
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• 2006

In this paper, the plastic organic thin-film transistors (OTFTs) with $32{\ast}32$ array are presented. Flexible organic light emitting diodes (OLEDs) operated by OTFTs are fabricated with a novel lamination method and the results are also presented. OTFT pixels defined by photolithography, and pentacene deposited by thermal evaporation. Fabrication method and the performances of green PHOLEDs with high efficiency, stability, and electrical performance are discussed.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.975-978
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• 2008

Novel sulfur-containing aromatic compounds were developed as stable, high-performance organic semiconductors for OTFT applications. Of them, dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) consisting of six aromatic rings gave high quality thin films by vapor deposition, which acted as a superior FET channel showing FET mobility as high as $3.0\;cm^2V^{-1}s^{-1}$. On the other hand, highly soluble 2,7-dialkyl[1]benzothieno[3,2-b][1]benzothiophenes ($C_n$-BTBTs) gave solution-processible OTFTs with FET mobility higher than $1.0\;cm^2V^{-1}s^{-1}$.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.470-470
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• 2012

Organic thin film transistors (OTFTs) backplane constitute the active elements in new generations of plastic electronic devices for flexible display. The overall OTFTs performance is largely depended on the properties and quality of each layers of device material. In solution based process of organic semiconductors (OSCs), the interface state is most impediments to preferable performance. Generally, a threshold voltage (Vth) shift is usually exhibited when organic gate insulators (OGIs) are exposed in an ambient air condition. This phenomenon was caused by the absorbed polar components (i.e. oxygen and moisture) on the interface between OGIs and Soluble OSCs during the jetting process. For eliminating the polar component at the interface of OGI, the role of high vacuum seasoning on an OGI for all solution processable OTFTs were studied. Poly 4-vinly phenols (PVPs) were the material chosen as the organic gate dielectric, with a weakness in ambient air. The high vacuum seasoning of PVP's surface showed improved performance from non-seasoning TFT; a $V_{th}$, a ${\mu}_{fe}$ and a interface charge trap density from -8V, $0.018cm^2V^{-1}s^{-1}$, $1.12{\times}10^{-12}(cm^2eV)^{-1}$ to -4.02 V, $0.021cm^2V^{-1}s^{-1}$, $6.62{\times}10^{-11}(cm^2eV)^{-1}$. These results of OTFT device show that polar components were well eliminated by the high vacuum seasoning processes.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1364-1369
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• 2005

In this paper, we have identified the mechanism of C-V hysteresis behavior often observed in pentacene organic thin-film transistors (OTFTs). The capacitance-voltage (C-V) characteristics were measured for pentacene OTFTs fabricated on glass substrates with MoW as gate/source/drain electrode and TEOS $SiO_2$ as gate insulator. The measurements were made at room temperature and elevated temperatures. From the room temperature measurements, we found that the hysteresis behavior was caused by hole injection into the gate insulator from the pentacene semiconductor for large negative gate voltages, resulting in the negative flat-band voltage shift. However electron injection was observed only at elevated temperatures

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.151-154
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• 2007

We demonstrate a novel selective patterning process of a semiconducting polymer for channel regions to fabricate an array of organic thin-film transistors (OTFTs). This process is applicable for various organic films over large area. A reflective liquid crystal display based on the OTFT array was produced using the selective patterning through a wettability control.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.8
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• pp.7-12
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• 2010

In this paper, $C_{60}$ based Organic thin film transistor OTFTs) have been fabricated using BPhen(Bathophenanthroline) and BPhen doped with Cs interlayers between $C_{60}$ active layer and Al electrodes to improve the electrical performance. The addition of the BPhen layer resulted in enhanced performances by reducing surface roughness between organic-metal interface. And the contact resistance was reduced by using the BPhen doped with Cs interlayer with co-evaporation method. These performances suggests that the $C_{60}$ based OTFT with BPhen doped with Cs interlayer is a promising application in the fabrication of n-type organic transistors.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05a
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• pp.86-89
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• 2004

Organic thin film transistors (OTFTs) are fabricated on the plastic substrate through 4-level mask process without photolithographic patterning to yield the simple fabrication process. And we herewith report for the effect of dielectric surface modification on the electrical characteristics of OTFTs. The KIST-JM-1 as an organic molecule for the surface modification is deposited onto the surface of zirconium oxide $(ZrO_2)$ gate dielectric layer. In this work, we have examined the dependence of electrical performance on the interface surface state of gate dielectric/pentacene, which may be modified by chemical properties in the gate dielectric surface.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.11
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• pp.961-968
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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 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 $\textrm{cm}^2$/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 $\textrm{cm}^2$/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 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.