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Min-Koo Han

Bio: Min-Koo Han is an academic researcher from Seoul National University. The author has contributed to research in topics: Thin-film transistor & Breakdown voltage. The author has an hindex of 28, co-authored 515 publications receiving 3788 citations.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a new shift register employing bottom-gate In-Ga-Zn-O thin-film transistors (IGZO TFTs) was proposed and fabricated.
Abstract: A new shift register employing bottom-gate In-Ga-Zn-O thin-film transistors (IGZO TFTs) was proposed and fabricated. Depletion-mode IGZO TFTs were successfully turned off by employing two low-voltage-level signals. The IGZO shift register exhibited a high-voltage output pulse without any distortion and a maximum clock frequency of 417 kHz. The proposed shift register would be an important building block for a depletion-mode oxide TFT display.

101 citations

Journal ArticleDOI
TL;DR: In this article, a new hydrogenated amorphous silicon thin-film transistor (a-Si:H TFT) pixel circuit was proposed for an active matrix organic light-emitting diode (AMOLED) employing a voltage programming.
Abstract: We propose a new hydrogenated amorphous silicon thin-film transistor (a-Si:H TFT) pixel circuit for an active matrix organic light-emitting diode (AMOLED) employing a voltage programming. The proposed a-Si:H TFT pixel circuit, which consists of five switching TFTs, one driving TFT, and one capacitor, successfully minimizes a decrease of OLED current caused by threshold voltage degradation of a-Si:H TFT and OLED. Our experimental results, based on the bias-temperature stress, exhibit that the output current for OLED is decreased by 7% in the proposed pixel, while it is decreased by 28% in the conventional 2-TFT pixel.

99 citations

Journal ArticleDOI
TL;DR: In this paper, a voltage-modulated active-matrix organic light-emitting diode (AMOLED) pixel design, which successfully compensates for the threshold voltage variations in poly-Si thin-film transitors (TFTs), is proposed, and verified by SPICE simulation and experiments.
Abstract: A new voltage-modulated active-matrix organic light-emitting diode (AMOLED) pixel design, which successfully compensates for the threshold voltage variations in poly-Si thin-film transitors (TFTs), is proposed, and verified by SPICE simulation and experiments. In order to compensate for variations in OLED current, the proposed pixel design employs a new voltage modulation scheme using diode connections.

92 citations

Journal ArticleDOI
TL;DR: In this paper, a poly-Si thin-film transistor (TFT) current-mirror-active-matrix-organic-light-emitting-diode (AMOLED) pixel was designed and fabricated.
Abstract: A new poly-Si thin-film-transistor (TFT) current-mirror-active-matrix-organic-light-emitting-diode (AMOLED) pixel, which successfully compensates for the variation of the threshold voltage as well as mobility in the excimer laser annealed poly-Si TFT pixel, is designed and fabricated. The OLED current (IOLED) of the proposed pixel does not depend on the operating temperature. When the temperature of pixel is increased from 27 degC to 60 degC, the I OLED of the new pixel circuit composed of four TFTs and one capacitor increases only about 1.5%, while that of a conventional pixel composed of two TFTs and one capacitor increases about 37%. At room temperature, nonuniformity of the IOLED in the proposed circuit was also considerably suppressed at around 9%. We have successfully fabricated a 1.2-in AMOLED panel (96times96timesred green blue) to evaluate the performance of the proposed pixel. A troublesome residual image caused by the hysteresis phenomenon of the poly-Si TFT was almost eliminated in the proposed AMOLED panel as a result of current programming

82 citations

Journal ArticleDOI
TL;DR: In this paper, the degradation of indium-gallium-zincoxide (IGZO) thin-film transistors (TFTs) for various channel widths under high-gate and drain bias stress was investigated.
Abstract: We investigated the degradation of indium-gallium-zinc-oxide (IGZO) thin-film transistors (TFTs) for various channel widths under high-gate and drain bias stress. The threshold voltage of IGZO TFT with wide-channel width (W > 100 μm) was significantly shifted. This included stress-induced hump-effect in a negative direction after the stress, whereas IGZO TFT with narrow-channel width (W < 100 μm) shifted in a positive direction. This phenomenon may be attributed to the hole trapping into the back-interface region. In order to enhance the reliability of IGZO TFTs, we developed and verified that the multiple-channel device showed better bias-temperature stability (ΔVTH: −0.1 V), whereas the single-channel device exhibited a −0.4 VΔVTH shift.

82 citations


Cited by
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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
TL;DR: The recent progress in n- and p-type oxide based thin-film transistors (TFT) is reviewed, with special emphasis on solution-processed andp-type, and the major milestones already achieved with this emerging and very promising technology are summarizeed.
Abstract: Transparent electronics is today one of the most advanced topics for a wide range of device applications. The key components are wide bandgap semiconductors, where oxides of different origins play an important role, not only as passive component but also as active component, similar to what is observed in conventional semiconductors like silicon. Transparent electronics has gained special attention during the last few years and is today established as one of the most promising technologies for leading the next generation of flat panel display due to its excellent electronic performance. In this paper the recent progress in n- and p-type oxide based thin-film transistors (TFT) is reviewed, with special emphasis on solution-processed and p-type, and the major milestones already achieved with this emerging and very promising technology are summarizeed. After a short introduction where the main advantages of these semiconductors are presented, as well as the industry expectations, the beautiful history of TFTs is revisited, including the main landmarks in the last 80 years, finishing by referring to some papers that have played an important role in shaping transparent electronics. Then, an overview is presented of state of the art n-type TFTs processed by physical vapour deposition methods, and finally one of the most exciting, promising, and low cost but powerful technologies is discussed: solution-processed oxide TFTs. Moreover, a more detailed focus analysis will be given concerning p-type oxide TFTs, mainly centred on two of the most promising semiconductor candidates: copper oxide and tin oxide. The most recent data related to the production of complementary metal oxide semiconductor (CMOS) devices based on n- and p-type oxide TFT is also be presented. The last topic of this review is devoted to some emerging applications, finalizing with the main conclusions. Related work that originated at CENIMAT|I3N during the last six years is included in more detail, which has led to the fabrication of high performance n- and p-type oxide transistors as well as the fabrication of CMOS devices with and on paper.

2,440 citations

Journal ArticleDOI
TL;DR: This Progress Report provides an update on recent developments in inkjet printing technology and its applications, which include organic thin-film transistors, light-emitting diodes, solar cells, conductive structures, memory devices, sensors, and biological/pharmaceutical tasks.
Abstract: In this Progress Report we provide an update on recent developments in inkjet printing technology and its applications, which include organic thin-film transistors, light-emitting diodes, solar cells, conductive structures, memory devices, sensors, and biological/pharmaceutical tasks. Various classes of materials and device types are in turn examined and an opinion is offered about the nature of the progress that has been achieved.

2,019 citations

Journal ArticleDOI
TL;DR: The role of defects and impurities on the transport and optical properties of bulk, epitaxial, and nanostructures material, the difficulty in p-type doping, and the development of processing techniques like etching, contact formation, dielectrics for gate formation, and passivation are discussed in this article.
Abstract: Gallium oxide (Ga2O3) is emerging as a viable candidate for certain classes of power electronics, solar blind UV photodetectors, solar cells, and sensors with capabilities beyond existing technologies due to its large bandgap. It is usually reported that there are five different polymorphs of Ga2O3, namely, the monoclinic (β-Ga2O3), rhombohedral (α), defective spinel (γ), cubic (δ), or orthorhombic (e) structures. Of these, the β-polymorph is the stable form under normal conditions and has been the most widely studied and utilized. Since melt growth techniques can be used to grow bulk crystals of β-GaO3, the cost of producing larger area, uniform substrates is potentially lower compared to the vapor growth techniques used to manufacture bulk crystals of GaN and SiC. The performance of technologically important high voltage rectifiers and enhancement-mode Metal-Oxide Field Effect Transistors benefit from the larger critical electric field of β-Ga2O3 relative to either SiC or GaN. However, the absence of clear demonstrations of p-type doping in Ga2O3, which may be a fundamental issue resulting from the band structure, makes it very difficult to simultaneously achieve low turn-on voltages and ultra-high breakdown. The purpose of this review is to summarize recent advances in the growth, processing, and device performance of the most widely studied polymorph, β-Ga2O3. The role of defects and impurities on the transport and optical properties of bulk, epitaxial, and nanostructures material, the difficulty in p-type doping, and the development of processing techniques like etching, contact formation, dielectrics for gate formation, and passivation are discussed. Areas where continued development is needed to fully exploit the properties of Ga2O3 are identified.

1,535 citations

Patent
01 Aug 2008
TL;DR: In this article, the oxide semiconductor film has at least a crystallized region in a channel region, which is defined as a region of interest (ROI) for a semiconductor device.
Abstract: An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.

1,501 citations