• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.1
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• pp.31-37
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• 2009

Hybrid ballast for field emission lamp with CNT (carbon nano tube) emitter is proposed. Hybrid ballast consists of a high voltage dc part and hi-polar pulse generation part. Field emission lamp with CNT lamp is composed of three electrodes (anode, gate, and cathode). High voltage dc part is for anode and gate and hi-polar pulse generation part is for gate and cathode in CNT triode respectively. The experimental results demonstrate that the proposed topology is good for driving CNT lamp. To protect the lamp and ballast, OCP (Over Current Protection), OVP (Over Voltage Protection), and OTP (Over Temperature Protection) are added and the experimental results demonstrate that the proposed method is good for driving field emission lamp with CNT emitter.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.10
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• pp.678-686
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• 2001

Origins for the transconductance dispersion and the gate leakage current in a GaAs metal semiconductor field effect transistor were found using capacitance deep-level transient spectroscopy (DLTS) measurements. In DLTS spectra, we observed two surface states with thermal activation energies of 0.65 $\times$ 0.07 eV and 0.88 $\times$ 0.04 eV and an electron trap EL2 with thermal activation energy of 0.84 $\times$ 0.01 eV. Transconductance was decreased in the frequency range of 5.5 Hz ~ 300 Hz. The transition frequency shifted to higher frequencies with the increase of temperature and the activation energy for the change of the transition frequency was determined to be 0.66 $\times$ 0.02 eV. From the measurements of the gate leakage current as a function of the device temperature, the forward and reverse currents are coincident with each other below gate voltages lower than 0.15 V, namely Ohmic behavior between gate and source/drain electrodes. The activation energy for the conductance of electrons on the surface of MESFET was 0.63 $\times$ 0.01 eV. Comparing activation energies obtained by different measurements, we found surface states H1 caused the transconductance dispersion and the fate leakage current.

• Proceedings of the IEEK Conference
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• 2004.06b
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• pp.489-492
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• 2004

In this paper, we demonstrate polymer thin-film transistors (TFTs) on a paper-based flexible substrate. As a substrate, commercially available photo-paper is used with Parylene coating. The parylene layer enables conventionally used wet chemical process and vacuum deposition processes for electrodes and gate insulator. As an active channel layer, we used poly-3-hexylthiophene (P3HT) which is solution process. Field effect mobility up to $(0.06 {\pm} 0.02) cm^2/Vs$ and on/off ratio of $10^3 {\~}10^4$ are achieved on a photo-paper.

• Journal of Sensor Science and Technology
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• v.26 no.2
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• pp.79-84
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• 2017

The drain current of the SB MOSFET was analytically modeled by an equation composed of thermionic emission and tunneling with consideration of the image force lowering. The depletion region electron concentration was used to model the channel electron concentration for the tunneling current. The Schottky barrier width is dependent on the channel electron concentration. The drain current is changed by the gate oxide thickness and Schottky barrier height, but it is hardly changed by the doping concentration. For a GaN SB MOSFET with ITO source and drain electrodes, the calculated threshold voltage was 3.5 V which was similar to the measured value of 3.75 V and the calculated drain current was 1.2 times higher than the measured.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.441-445
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• 2007

In this paper we demonstrated the applications of OTFTs (organic thin film transistors) to flexible displays such as AM-EPD (active matrix electrophoretic display) and AM-OLED (active matrix organic light emitting diode), and also to integrated circuits. The OTFTs using pentacene semiconductor layer and PVP gate dielectric and Au S/D electrodes exhibited good performance for AM-EPD with the mobility of $0.59\;cm^{2}/V.sec,$ and with also good uniformity over 2.5" diagonal area. However, it is nor enough for AM-OLED requiring the mobility larger than $1\;cm^{2}/V.sec$ for large area displays. The integrated circuits also worked, producing the operating frequency of 1MHz. We need to develop a fabrication process to reduce parasitic capacitance for high frequency operation.

• Transactions on Electrical and Electronic Materials
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• v.4 no.4
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• pp.26-29
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• 2003

To discover electrical properties of individual single wall nanotube(SWNT), a number of SWNT-based tubeFETs have been fabricated. The device consists of a single semiconducting SWNT on an insulating substrate, contacted at each end by metal electrodes. It presents high transconductances, and charge storage phenomenon, which is the operations of injecting electrons from the nanotube channel of a tubeFET into charge traps on the surface of the $SiO_2$ gate dielectric, thus shifting the threshold voltage. This phenomenon can be repeated many times, and maintained for the hundreds of seconds at room temperature. We will report this phenomenon as the memory effects of the SWNT, and attempt to use this property for the memory device.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.629-632
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• 2008

Printed organic thin-film transistors (OTFTs) were used in the fabrication of a screen- printed gate, source and drain electrodes on flexible plastic substrates using silver pastes, a coated polyvinylphenol dielectrics, and jetted bis(triisopropyl-silylethynyl) pentacene (TIPS-pentacene) organic semiconductor. The OTFTs printed using screen printing and soluble processes made it was possible to fabricate a printed OTFT with a channel length as small as $13\;{\mu}m$ on plastic substrates; this was not possible using previous traditional printing techniques.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.443-445
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• 2008

We have fabricated vertical type organic thin film transistor using $C_{60}$ as a n-type active material to improve the problems of conventional OTFTs. In general, it can be argued that the characteristics of organic transistor were influenced by carrier mobility and density. We have used several kinds of metals as source and gate electrodes to optimize the device characteristics using $C_{60}$. In addition, we have examined the feasibility of fabrication of organic light-emitting transistor (OLET) using MEH-PPV as an emission layer.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.290-293
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• 2006

We designed the H-IPS that has similar aperture ratio to the AS-IPS with organic insulator. To improve the aperture ratio without organic insulator, we positioned the pixel electrode over the preceding gate on the base of the H-IPS structure, and minimized the width of pixel and common electrodes. Without the additional process, we could obtain the similar brightness with that of AS-IPS in 15inch SXGA+ Panel.

• ETRI Journal
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• v.20 no.2
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• pp.241-249
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• 1998

The structure and electrical characteristics of metal-ferroelectric-semiconductor FET(MFSFET) for a single transistor memory are presented. The MFSFET was comprised of polysilicon islands as source/drain electrodes and $BaMgF_4$ film as a gate dielectric. The polysilicon source and drain were built-up prior to the formation of the ferroelectric film to suppress a degradation of the film due to high thermal cycles. From the MFS capacitor, the remnant polarization and coercive field were measured to be about $0.6{\mu}C/cm^2$ and 100 kV/cm, respectively. The fabricated MFSFETs also showed good hysteretic I-V curves, while the current levels disperse probably due to film cracking or bad adhesion between the film and the Al electrode.