27 results on '"Geun Woo Baek"'
Search Results
2. Progress in the development of the display performance of AR, VR, QLED and OLED devices in recent years
- Author
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Ho Jin Jang, Jun Yeob Lee, Geun Woo Baek, Jeonghun Kwak, and Jae-Hyeung Park
- Subjects
ar ,vr ,qled ,oled ,Computer engineering. Computer hardware ,TK7885-7895 - Abstract
The remarkable progress of virtual reality, augmented reality, quantum dot light-emitting diode, and organic light-emitting diode as next-generation displays has overcome the leadership of the liquid crystal display during the last two years. This paper discusses the key technological advancements and performance of these new-generation display devices.
- Published
- 2022
- Full Text
- View/download PDF
3. Scalable and selective N-type conversion for carbon nanotube transistors via patternable polyvinyl alcohol stacked with hydrophobic layers and their application to complementary logic circuits
- Author
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Seungyeob Kim, Geun Woo Baek, Jinheon Jeong, Seung Gi Seo, and Sung Hun Jin
- Subjects
Carbon nanotubes ,Nanotube separation ,Thin-film transistors ,n-type transistors ,CMOS integrated Circuits ,Mining engineering. Metallurgy ,TN1-997 - Abstract
Herein, this study reports scalable and selective n-type conversion (N/C) approach for single walled carbon nanotube (SWNT) transistors with high reproducibility by using novel control of hydroxyl groups through condensation on the surface of SWNTs, via the patternable cross-linked polyvinyl alcohol (C-PVA), followed by encapsulation of photo-definable hydrophobic polymer (~SU8). Moreover, N/C process capability is statistically evaluated in terms of selective doping, process yield, and statistical variation in electrical parameters, and as practical validation, complementary inverters, NOR and NAND logic gates are fully demonstrated. As one of key findings, it is elucidated that N/C uniformity and its underlying physics, supported by Fourier-transform infrared spectroscopy (FTIR) and Raman analysis, are highly correlated with ambient condition, C-PVA thickness, and encapsulation. More practically, reproducible field effect mobility for n-type (or p-type) SWNT TFTs after (or before) N/C are achieved at ~ 3.65 ± 1.30 (or 8.76 ± 2.16) cm2 V−1 s−1, with magnificent process yield (~100%) and reasonable mobility reduction, which is on par with the previous report. Hence, all demonstration and their analyses suggest that this scalable N/C scheme for SWNT TFTs can be one of core technologies for the next generation semiconductor-based devices and their envisioned application.
- Published
- 2021
- Full Text
- View/download PDF
4. Progress in the Development of Active-Matrix Quantum-Dot Light-Emitting Diodes Driven by Non-Si Thin-Film Transistors
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Geun Woo Baek, Yeon Jun Kim, Minhyung Lee, Yeunwoo Kwon, Beomsoo Chun, Ganghyun Park, Hansol Seo, Heesun Yang, and Jeonghun Kwak
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active-matrix ,quantum-dot light-emitting diodes ,thin film transistors ,metal oxides ,transition metal dichalcogenides ,carbon nanotubes ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
This paper aims to discuss the key accomplishments and further prospects of active-matrix (AM) quantum-dot (QD) light-emitting diodes (QLEDs) display. We present an overview and state-of-the-art of QLEDs as a frontplane and non-Si-based thin-film transistors (TFTs) as a backplane to meet the requirements for the next-generation displays, such as flexibility, transparency, low power consumption, fast response, high efficiency, and operational reliability. After a brief introduction, we first review the research on non-Si-based TFTs using metal oxides, transition metal dichalcogenides, and semiconducting carbon nanotubes as the driving unit of display devices. Next, QLED technologies are analyzed in terms of the device structure, device engineering, and QD patterning technique to realize high-performance, full-color AM-QLEDs. Lastly, recent research on the monolithic integration of TFT–QLED is examined, which proposes a new perspective on the integrated device. We anticipate that this review will help the readership understand the fundamentals, current state, and issues on TFTs and QLEDs for future AM-QLED displays.
- Published
- 2022
- Full Text
- View/download PDF
5. Effect of Excess Carriers on the Degradation of InP-Based Quantum-Dot Light-Emitting Diodes
- Author
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Kyunghwan Kim, Donghyo Hahm, Geun Woo Baek, Taesoo Lee, Doyoon Shin, Jaemin Lim, Wan Ki Bae, and Jeonghun Kwak
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Materials Chemistry ,Electrochemistry ,Electronic, Optical and Magnetic Materials - Published
- 2022
6. Device design and fabrication process of quantum dot light-emitting diodes for full-color displays and lighting sources (Conference Presentation)
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Taesoo Lee, Geun Woo Baek, and Jeonghun Kwak
- Published
- 2022
7. Scalable and selective N-type conversion for carbon nanotube transistors via patternable polyvinyl alcohol stacked with hydrophobic layers and their application to complementary logic circuits
- Author
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Jinheon Jeong, Seungyeob Kim, Geun Woo Baek, Seung Gi Seo, and Sung Hun Jin
- Subjects
Materials science ,Thin-film transistors ,Carbon nanotubes ,Field effect ,02 engineering and technology ,Carbon nanotube ,01 natural sciences ,Polyvinyl alcohol ,law.invention ,Biomaterials ,chemistry.chemical_compound ,CMOS integrated Circuits ,law ,0103 physical sciences ,Nanotube separation ,n-type transistors ,010302 applied physics ,Mining engineering. Metallurgy ,business.industry ,Doping ,TN1-997 ,Metals and Alloys ,021001 nanoscience & nanotechnology ,NAND logic ,Surfaces, Coatings and Films ,Carbon nanotube field-effect transistor ,Semiconductor ,chemistry ,Logic gate ,Ceramics and Composites ,Optoelectronics ,0210 nano-technology ,business - Abstract
Herein, this study reports scalable and selective n-type conversion (N/C) approach for single walled carbon nanotube (SWNT) transistors with high reproducibility by using novel control of hydroxyl groups through condensation on the surface of SWNTs, via the patternable cross-linked polyvinyl alcohol (C-PVA), followed by encapsulation of photo-definable hydrophobic polymer (~SU8). Moreover, N/C process capability is statistically evaluated in terms of selective doping, process yield, and statistical variation in electrical parameters, and as practical validation, complementary inverters, NOR and NAND logic gates are fully demonstrated. As one of key findings, it is elucidated that N/C uniformity and its underlying physics, supported by Fourier-transform infrared spectroscopy (FTIR) and Raman analysis, are highly correlated with ambient condition, C-PVA thickness, and encapsulation. More practically, reproducible field effect mobility for n-type (or p-type) SWNT TFTs after (or before) N/C are achieved at ~ 3.65 ± 1.30 (or 8.76 ± 2.16) cm2 V−1 s−1, with magnificent process yield (~100%) and reasonable mobility reduction, which is on par with the previous report. Hence, all demonstration and their analyses suggest that this scalable N/C scheme for SWNT TFTs can be one of core technologies for the next generation semiconductor-based devices and their envisioned application.
- Published
- 2021
8. A Bioinspired Stretchable Sensory-Neuromorphic System
- Author
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Sun Hong Kim, Geun Woo Baek, Jiyong Yoon, Seunghwan Seo, Donghyo Hahm, Jun Hyuk Chang, Duhwan Seong, Hyunseon Seo, Seyong Oh, Kyunghwan Kim, Heeyoung Jung, Youngsu Oh, Hyoung Won Baac, Batyrbek Alimkhanuly, Wan Ki Bae, Seunghyun Lee, Jeonghun Kwak, Jin-Hong Park, and Donghee Son
- Abstract
Conventional stretchable electronics entailing the adoption of a wavy design, a neutral mechanical plane, and a conformal contact between abiotic and biotic interfaces have shown diverse skin-interfaced applications. Despite such remarkable progress, there have been challenged to be evolved to intelligent skin prosthetics due to the absence of the monolithic integration of neuromorphic constituents into individual sensing and actuating components. Herein, we demonstrate a golden tortoise beetle-inspired stretchable sensory-neuromorphic system comprising an artificial mechanoreceptor, an artificial synapse, and an epidermal photonic actuator as three biomimetic functionalities that correspond to a stretchable capacitive pressure sensor, a resistive random-access memory, and a quantum dot light-emitting diode, respectively. This system features a rigid-island structure interconnected with a sinter-free printable conductor (stretchability ~ 160%, conductivity ~ 18,550 S/cm), which allows one to improve both areal density and structural reliability while avoiding the thermal degradation of heat-sensitive stretchable electronic components. Moreover, even in the skin deformation range, the system accurately recognizes various patterned stimuli via an artificial neural network with training/inferencing functions. Our new bioinspired system is therefore expected to be an important step toward the implementation of intelligent wearable electronics.
- Published
- 2020
9. Fabrication Process of Organic and Quantum Dot-Based Light-Emitting Diodes for Full-Color Display
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Suhyeon Lee, Seyoung Oh, Geun Woo Baek, and Jeonghun Kwak
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General Medicine - Published
- 2021
10. One-step solvothermal synthesis of carnation flower-like SnS 2 as superior electrodes for supercapacitor applications
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Sung Hun Jin, Geun Woo Baek, Hyuck-In Kwon, Rajneesh Kumar Mishra, and Kyuwon Kim
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Supercapacitor ,Materials science ,Solvothermal synthesis ,Analytical chemistry ,General Physics and Astronomy ,02 engineering and technology ,Surfaces and Interfaces ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Capacitance ,0104 chemical sciences ,Surfaces, Coatings and Films ,X-ray photoelectron spectroscopy ,Electrode ,Cyclic voltammetry ,0210 nano-technology ,Current density ,Power density - Abstract
We report the synthesis of carnation flower-like SnS2 (CF-SnS2) via a one-step solvothermal method for potential application as supercapacitor electrodes in energy storage devices. The structural and morphological properties of CF-SnS2 were characterized by X-ray diffraction, Raman analysis, and field-emission scanning and transmission electron microscopies. X-ray photoelectron spectroscopy and scanning tunneling electron microscopy with color mapping verified the distribution of Sn and S, and depicted the successful formation of SnS2. Electrochemical studies were performed to explore the supercapacitive nature of CF-SnS2. Supercapacitors with CF-SnS2 electrodes delivered excellent cyclic voltammetry performances, superior gravimetric specific capacitances, and high power densities. The evaluated specific capacitance and power density reached ∼524.5 F/g and 12.3 W/kg, respectively, at a current density of 0.08 A/g, and ∼215.9 F/g and 61.4 W/kg, respectively, at a current density of 0.38 A/g. These values are at least two times higher than those previously reported. The long-term cyclic stability was also tested to demonstrate the endurance of the CF-SnS2-based supercapacitor, with a 66% rate retention and galvanostatic charge/discharge reversibility. These electrochemical findings indicate that CF-SnS2 is a promising candidate for electrode materials in supercapacitor applications.
- Published
- 2017
11. A Bioinspired Stretchable Sensory‐Neuromorphic System
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Sun Hong Kim, Geun Woo Baek, Jiyong Yoon, Seunghwan Seo, Jinhong Park, Donghyo Hahm, Jun Hyuk Chang, Duhwan Seong, Hyunseon Seo, Seyong Oh, Kyunghwan Kim, Heeyoung Jung, Youngsu Oh, Hyoung Won Baac, Batyrbek Alimkhanuly, Wan Ki Bae, Seunghyun Lee, Minbaek Lee, Jeonghun Kwak, Jin‐Hong Park, and Donghee Son
- Subjects
Resistive touchscreen ,Materials science ,business.industry ,Mechanical Engineering ,Capacitive sensing ,Stretchable electronics ,Nanotechnology ,Resistive random-access memory ,Wearable Electronic Devices ,Neuromorphic engineering ,Mechanics of Materials ,visual_art ,Electronic component ,visual_art.visual_art_medium ,General Materials Science ,Photonics ,Actuator ,business - Abstract
Conventional stretchable electronics that adopt a wavy design, a neutral mechanical plane, and conformal contact between abiotic and biotic interfaces have exhibited diverse skin-interfaced applications. Despite such remarkable progress, the evolution of intelligent skin prosthetics is challenged by the absence of the monolithic integration of neuromorphic constituents into individual sensing and actuating components. Herein, a bioinspired stretchable sensory-neuromorphic system, comprising an artificial mechanoreceptor, artificial synapse, and epidermal photonic actuator is demonstrated; these three biomimetic functionalities correspond to a stretchable capacitive pressure sensor, a resistive random-access memory, and a quantum dot light-emitting diode, respectively. This system features a rigid-island structure interconnected with a sinter-free printable conductor, which is optimized by controlling the evaporation rate of solvent (≈160% stretchability and ≈18 550 S cm-1 conductivity). Devised design improves both areal density and structural reliability while avoiding the thermal degradation of heat-sensitive stretchable electronic components. Moreover, even in the skin deformation range, the system accurately recognizes various patterned stimuli via an artificial neural network with training/inferencing functions. Therefore, the new bioinspired system is expected to be an important step toward implementing intelligent wearable electronics.
- Published
- 2021
12. Highly Efficient, Surface Ligand Modified Quantum Dot Light‐Emitting Diodes Driven by Type‐Controllable MoTe 2 Thin Film Transistors via Electron Charge Enhancer
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Seung Gi Seo, Geun Woo Baek, Wan Ki Bae, Sung Hun Jin, Jeonghun Kwak, and Donghyo Hahm
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Surface (mathematics) ,Materials science ,business.industry ,Ligand ,Electric charge ,Electronic, Optical and Magnetic Materials ,law.invention ,Thin-film transistor ,Quantum dot ,law ,Optoelectronics ,business ,Enhancer ,Light-emitting diode - Published
- 2021
13. Simultaneous Detection of Dopamine and Uric Acid on Indium Tin Oxides Modified with Cost-effective Gas-phase Synthesized Single Walled Carbon Nanotubes
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Sung Hun Jin, Geun Woo Baek, Md. Mohibul Islam Khan, Hyuck-In Kwon, and Kyuwon Kim
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Detection limit ,Materials science ,010401 analytical chemistry ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,Carbon nanotube ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,law.invention ,chemistry ,law ,Electrochemistry ,Surface modification ,Differential pulse voltammetry ,Cyclic voltammetry ,0210 nano-technology ,Tin ,Biosensor ,Indium - Abstract
Cost-effective gas-phase synthesized single walled carbon nanotubes (SWCNTs) were first employed for the surface modification of indium tin oxides (ITO) via electrostatic coating of poly-l-lysine (PLL). Compared with control substrates of bare ITO and SWCNT-PLL-slide glasses, SWCNT-PLL-ITO, with high catalytic properties associated with large surface areas, showed significant improvement of electro catalytic activity toward the oxidation of dopamine (DA) and uric acid (UA). The cyclic voltammetric (CV) peak separation of oxidation for both DA and UA was estimated to be ∼ 0.13 V, which renders them capable of simultaneously detecting DA and UA in a mixed solution. The differential pulse voltammetry (DPV) technique was further performed to obtain a linear detection range of DA from 1.0 μM to 100 μM, and a detection limit of 1.0 μM was confirmed in the mixed solution. Furthermore, the practical analytical ability of the method was finally confirmed by selective detection of both DA and UA in human urine samples without any preliminary treatment, implying the feasibility of applying bio-sensors in a low-cost manner.
- Published
- 2017
14. P-32: Light Shielding Layers Enabled Full Swing Multi-Layer MoS2 Inverters For the Application of Photodetectors
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Seung Jae Yu, Jae Hyeon Ryu, Sung Hun Jin, Geun Woo Baek, and Seung Gi Seo
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Materials science ,business.industry ,Electromagnetic shielding ,Photodetector ,Optoelectronics ,Swing ,business ,Multi layer - Published
- 2017
15. Photosensitive Full-Swing Multi-Layer MoS2Inverters With Light Shielding Layers
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Seung Gi Seo, Geun Woo Baek, Jae Hyeon Ryu, Seung Jae Yu, and Sung Hun Jin
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010302 applied physics ,Materials science ,business.industry ,Band gap ,Physics::Optics ,Photodetector ,02 engineering and technology ,Swing ,021001 nanoscience & nanotechnology ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Wavelength ,Thin-film transistor ,Logic gate ,0103 physical sciences ,Electromagnetic shielding ,Optoelectronics ,Electrical and Electronic Engineering ,0210 nano-technology ,business ,Diode - Abstract
Multi-layered MoS2 inverters with light shielding layers were fabricated and demonstrated for application in highly sensitive photodetectors, exploiting the particular advantages of an atomically thin layer and a sizable electrical bandgap. The photoleakage behaviors of the inverters under changing wavelengths of light were experimentally demonstrated to occur in a controlled manner and were analytically validated by load-line analysis. When the inverters were operated with a depletion load in the light of blue light emitting diodes, the low noise margin and transition width were significantly enhanced, by approximately 20% and 220%, respectively, as compared with those of the inverters in the dark.
- Published
- 2017
16. Threshold Voltage Control of Multilayered MoS
- Author
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Jeongkyun, Roh, Jae Hyeon, Ryu, Geun Woo, Baek, Heeyoung, Jung, Seung Gi, Seo, Kunsik, An, Byeong Guk, Jeong, Doh C, Lee, Byung Hee, Hong, Wan Ki, Bae, Jong-Ho, Lee, Changhee, Lee, and Sung Hun, Jin
- Abstract
In recent past, for next-generation device opportunities such as sub-10 nm channel field-effect transistors (FETs), tunneling FETs, and high-end display backplanes, tremendous research on multilayered molybdenum disulfide (MoS
- Published
- 2018
17. Field-Effect Transistors: Threshold Voltage Control of Multilayered MoS2 Field-Effect Transistors via Octadecyltrichlorosilane and their Applications to Active Matrixed Quantum Dot Displays Driven by Enhancement-Mode Logic Gates (Small 7/2019)
- Author
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Sung Hun Jin, Seung Gi Seo, Doh C. Lee, Heeyoung Jung, Jong-Ho Lee, Jae Hyeon Ryu, Kunsik An, Jeongkyun Roh, Byung Hee Hong, Wan Ki Bae, Byeong Guk Jeong, Geun Woo Baek, and Changhee Lee
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Materials science ,business.industry ,General Chemistry ,Octadecyltrichlorosilane ,Threshold voltage ,Biomaterials ,chemistry.chemical_compound ,Mode (computer interface) ,chemistry ,Quantum dot ,Logic gate ,Optoelectronics ,General Materials Science ,Field-effect transistor ,business ,Biotechnology - Published
- 2019
18. Threshold Voltage Control of Multilayered MoS2 Field-Effect Transistors via Octadecyltrichlorosilane and their Applications to Active Matrixed Quantum Dot Displays Driven by Enhancement-Mode Logic Gates
- Author
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Wan Ki Bae, Seung Gi Seo, Jeongkyun Roh, Jae Hyeon Ryu, Byeong Guk Jeong, Byung Hee Hong, Sung Hun Jin, Heeyoung Jung, Changhee Lee, Geun Woo Baek, Jong-Ho Lee, Doh C. Lee, and Kunsik An
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Materials science ,business.industry ,Transistor ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Threshold voltage ,law.invention ,Biomaterials ,Noise margin ,Quantum dot ,law ,Logic gate ,Optoelectronics ,General Materials Science ,Field-effect transistor ,0210 nano-technology ,business ,Biotechnology ,Diode ,Voltage - Abstract
In recent past, for next-generation device opportunities such as sub-10 nm channel field-effect transistors (FETs), tunneling FETs, and high-end display backplanes, tremendous research on multilayered molybdenum disulfide (MoS2 ) among transition metal dichalcogenides has been actively performed. However, nonavailability on a matured threshold voltage control scheme, like a substitutional doping in Si technology, has been plagued for the prosperity of 2D materials in electronics. Herein, an adjustment scheme for threshold voltage of MoS2 FETs by using self-assembled monolayer treatment via octadecyltrichlorosilane is proposed and demonstrated to show MoS2 FETs in an enhancement mode with preservation of electrical parameters such as field-effect mobility, subthreshold swing, and current on-off ratio. Furthermore, the mechanisms for threshold voltage adjustment are systematically studied by using atomic force microscopy, Raman, temperature-dependent electrical characterization, etc. For validation of effects of threshold voltage engineering on MoS2 FETs, full swing inverters, comprising enhancement mode drivers and depletion mode loads are perfectly demonstrated with a maximum gain of 18.2 and a noise margin of ≈45% of 1/2 VDD . More impressively, quantum dot light-emitting diodes, driven by enhancement mode MoS2 FETs, stably demonstrate 120 cd m-2 at the gate-to-source voltage of 5 V, exhibiting promising opportunities for future display application.
- Published
- 2019
19. Fluorinated CYTOP passivation effects on the electrical reliability of multilayer MoS₂ field-effect transistors
- Author
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Jeongkyun, Roh, In-Tak, Cho, Hyeonwoo, Shin, Geun Woo, Baek, Byung Hee, Hong, Jong-Ho, Lee, Sung Hun, Jin, and Changhee, Lee
- Abstract
We demonstrated highly stable multilayer molybdenum disulfide (MoS2) field-effect transistors (FETs) with negligible hysteresis gap (ΔV(HYS) ∼ 0.15 V) via a multiple annealing scheme, followed by systematic investigation for long-term air stability with time (∼50 days) of MoS2 FETs with (or without) CYTOP encapsulation. The extracted lifetime of the device with CYTOP passivation in air was dramatically improved from 7 to 377 days, and even for the short-term bias stability, the experimental threshold voltage shift, outstandingly well-matched with the stretched exponential function, indicates that the device without passivation has approximately 25% larger the barrier distribution (ΔE(B) = k(B)T(o)) than that of a device with passivation. This work suggests that CYTOP encapsulation can be an efficient method to isolate external gas (O2 and H2O) effects on the electrical performance of FETs, especially with low-dimensional active materials like MoS2.
- Published
- 2015
20. Spray-coated single walled carbon nanotubes as source and drain electrodes in SnO thin-film transistors
- Author
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Sung Hun Jin, Hyuck-In Kwon, Geun Woo Baek, Seung Yeob Kim, and Jae Hyeon Ryu
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010302 applied physics ,Materials science ,business.industry ,Contact resistance ,Field effect ,02 engineering and technology ,Carbon nanotube ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Electrical contacts ,Electronic, Optical and Magnetic Materials ,law.invention ,law ,Etching (microfabrication) ,Thin-film transistor ,0103 physical sciences ,Electrode ,Materials Chemistry ,Optoelectronics ,Electrical and Electronic Engineering ,0210 nano-technology ,business ,Layer (electronics) - Abstract
In this letter, spray-coated single walled carbon nanotubes (SWNTs) as one of alternative electrodes in SnO thin-film transistors are demonstrated for emerging electronic applications. Herein, the device architecture of SnO TFTs with a polymer etch stop layer (SU-8) enables the selective etching of SWNTs in a desired region without the detrimental effects of SnO channel layers. Moreover, SnO TFTs with SWNT electrodes as substitutes successfully demonstrate decent width normalized electrical contact properties (~1.49 kΩ cm), field effect mobility (~0.69 cm2 V−1 s−1), sub-threshold slope (~0.4 V dec−1), and current on–off ratio (I on/I off ~ 3.5 × 103). Systematic temperature dependency measurements elucidate that SnO channel transports with an activation energy within several tens of meV, together with decent contact resistance as compared to that of conventional Ni electrodes.
- Published
- 2018
21. Water-soluble thin film transistors and circuits based on amorphous indium-gallium-zinc oxide
- Author
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Seung-Kyun Kang, Jong-Ho Lee, Jongmin Shin, Dong Joon Lee, Ha Uk Chung, In-Tak Cho, John A. Rogers, Tae Il Kim, Sung Hun Jin, Geun Woo Baek, and Sang Youn Han
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Vinyl alcohol ,Materials science ,Transistors, Electronic ,Oxide ,Field effect ,chemistry.chemical_element ,Biocompatible Materials ,Gallium ,Indium ,chemistry.chemical_compound ,Materials Testing ,General Materials Science ,Ohmic contact ,Dissolution ,business.industry ,Water ,Equipment Design ,Amorphous solid ,Equipment Failure Analysis ,chemistry ,Solubility ,Thin-film transistor ,Molybdenum ,Optoelectronics ,Zinc Oxide ,business - Abstract
This paper presents device designs, circuit demonstrations, and dissolution kinetics for amorphous indium–gallium–zinc oxide (a-IGZO) thin film transistors (TFTs) comprised completely of water-soluble materials, including SiNx, SiOx, molybdenum, and poly(vinyl alcohol) (PVA). Collections of these types of physically transient a-IGZO TFTs and 5-stage ring oscillators (ROs), constructed with them, show field effect mobilities (∼10 cm2/Vs), on/off ratios (∼2 × 106), subthreshold slopes (∼220 mV/dec), Ohmic contact properties, and oscillation frequency of 5.67 kHz at supply voltages of 19 V, all comparable to otherwise similar devices constructed in conventional ways with standard, nontransient materials. Studies of dissolution kinetics for a-IGZO films in deionized water, bovine serum, and phosphate buffer saline solution provide data of relevance for the potential use of these materials and this technology in temporary biomedical implants.
- Published
- 2015
22. Fluorinated CYTOP passivation effects on the electrical reliability of multilayer MoS2 field-effect transistors
- Author
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In-Tak Cho, Jong-Ho Lee, Jeongkyun Roh, Geun Woo Baek, Byung Hee Hong, Hyeonwoo Shin, Sung Hun Jin, and Changhee Lee
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Stretched exponential function ,Materials science ,Passivation ,business.industry ,Annealing (metallurgy) ,Mechanical Engineering ,Transistor ,Bioengineering ,Nanotechnology ,General Chemistry ,law.invention ,Threshold voltage ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,law ,Optoelectronics ,Electrical performance ,General Materials Science ,Field-effect transistor ,Electrical and Electronic Engineering ,business ,Molybdenum disulfide - Abstract
We demonstrated highly stable multilayer molybdenum disulfide (MoS2) field-effect transistors (FETs) with negligible hysteresis gap (ΔV(HYS) ∼ 0.15 V) via a multiple annealing scheme, followed by systematic investigation for long-term air stability with time (∼50 days) of MoS2 FETs with (or without) CYTOP encapsulation. The extracted lifetime of the device with CYTOP passivation in air was dramatically improved from 7 to 377 days, and even for the short-term bias stability, the experimental threshold voltage shift, outstandingly well-matched with the stretched exponential function, indicates that the device without passivation has approximately 25% larger the barrier distribution (ΔE(B) = k(B)T(o)) than that of a device with passivation. This work suggests that CYTOP encapsulation can be an efficient method to isolate external gas (O2 and H2O) effects on the electrical performance of FETs, especially with low-dimensional active materials like MoS2.
- Published
- 2015
23. Enhancement mode p-channel SnO thin-film transistors with dual-gate structures
- Author
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Geun Woo Baek, Hyuck-In Kwon, Sang-Hun Song, Chan-Yong Jeong, Sung Hun Jin, Young Joon Han, and Yong-Jin Choi
- Subjects
Materials science ,business.industry ,Process Chemistry and Technology ,Transistor ,Dielectric ,Subthreshold slope ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Threshold voltage ,law.invention ,Thin-film transistor ,law ,Logic gate ,Electrode ,Materials Chemistry ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Instrumentation ,Leakage (electronics) - Abstract
The authors demonstrate the enhancement mode p-type SnO thin-film transistors (TFTs) using dual gate (DG) structures. The cross-linked polyvinyl alcohol dielectric with a polymethylmethacrylate buffer layer is formed as a top gate (TG) insulator of the DG SnO TFT. The fabricated DG SnO TFT exhibits better electrical performances than the bottom gate (BG) and TG SnO TFTs including higher field-effect mobility and smaller subthreshold slope. In fabricated DG TFTs, the threshold voltage (Vth) of the BG TFT is linearly modulated by the voltage applied to the TG electrode. The BG transfer curve exhibits a depletion mode operation when measured while TG is grounded, but operates in the enhancement mode with a negative Vth (=−0.9 V) when a positive bias of 10 V is applied to the TG electrode. The enhancement mode operation of p-type SnO TFTs can increase the output voltage swing range and decreases the off-stage leakage currents of the complementary logic circuits.
- Published
- 2015
24. Low frequency noise characteristics in multilayer WSe2 field effect transistor
- Author
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In-Tak Cho, Sung Hun Jin, Byung Hee Hong, Jeongkyun Roh, Jong-Ho Lee, Changhee Lee, Hyeonwoo Shin, Yoonki Hong, Jong-In Kim, and Geun Woo Baek
- Subjects
Electron mobility ,Noise power ,Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,Subthreshold conduction ,Infrasound ,Optoelectronics ,Spectral density ,Field-effect transistor ,Flicker noise ,business ,Power law - Abstract
This paper investigates the low-frequency noise properties of multilayer WSe2 field effect transistors (FETs) in subthreshold, linear, and saturation regime. The measured noise power spectral density of drain current (SID) shows that the low-frequency noise in multilayer WSe2 FET fits well to a 1/fγ power law with γ ∼ 1 in the frequency range of 10 Hz–200 Hz. From the dependence of SID on the drain current, carrier mobility fluctuation is considered as a dominant low frequency noise mechanism from all operation regimes in multilayer WSe2 FET. Extracted Hooge's parameter in this study is within the value of 0.12, comparable to those of the transition metal dichalcogenide FETs in recent reports.
- Published
- 2015
25. Enhancement mode p-channel SnO thin-film transistors with dual-gate structures.
- Author
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Yong-Jin Choi, Young-Joon Han, Chan-Yong Jeong, Sang-Hun Song, Geun Woo Baek, Sung Hun Jin, and Hyuck-In Kwon
- Subjects
THIN film transistors ,TIN oxides ,POLYVINYL alcohol ,POLYMETHYLMETHACRYLATE ,DIELECTRICS ,FIELD-effect transistors - Abstract
The authors demonstrate the enhancement mode p-type SnO thin-film transistors (TFTs) using dual gate (DG) structures. The cross-linked polyvinyl alcohol dielectric with a polymethylmethacrylate buffer layer is formed as a top gate (TG) insulator of the DG SnO TFT. The fabricated DG SnO TFT exhibits better electrical performances than the bottom gate (BG) and TG SnO TFTs including higher field-effect mobility and smaller subthreshold slope. In fabricated DG TFTs, the threshold voltage (V
th ) of the BG TFT is linearly modulated by the voltage applied to the TG electrode. The BG transfer curve exhibits a depletion mode operation when measured while TG is grounded, but operates in the enhancement mode with a negative Vth (=-0.9 V) when a positive bias of 10V is applied to the TG electrode. The enhancement mode operation of p-type SnO TFTs can increase the output voltage swing range and decreases the off-stage leakage currents of the complementary logic circuits. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
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26. Low frequency noise characteristics in multilayer WSe2 field effect transistor.
- Author
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In-Tak Cho, Jong In Kim, Yoonki Hong, Jeongkyun Roh, Hyeonwoo Shin, Geun Woo Baek, Changhee Lee, Byung Hee Hong, Sung Hun Jin, and Jong-Ho Lee
- Subjects
TUNGSTEN compounds ,SELENIUM compounds ,FIELD-effect transistors ,SPECTRAL energy distribution ,TRANSITION metals - Abstract
This paper investigates the low-frequency noise properties of multilayer WSe
2 field effect transistors (FETs) in subthreshold, linear, and saturation regime. The measured noise power spectral density of drain current (SID ) shows that the low-frequency noise in multilayer WSe2 FET fits well to a 1/fγ power law with γ ~ 1 in the frequency range of 10Hz-200Hz. From the dependence of SID on the drain current, carrier mobility fluctuation is considered as a dominant low frequency noise mechanism from all operation regimes in multilayer WSe2 FET. Extracted Hooge's parameter in this study is within the value of 0.12, comparable to those of the transition metal dichalcogenide FETs in recent reports. [ABSTRACT FROM AUTHOR]- Published
- 2015
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27. Spray-coated single walled carbon nanotubes as source and drain electrodes in SnO thin-film transistors.
- Author
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Jae Hyeon Ryu, Geun-Woo Baek, Seung Yeob Kim, Hyuck-In Kwon, and Sung Hun Jin
- Subjects
- *
SINGLE walled carbon nanotubes , *THIN film transistors , *ELECTRICAL properties of tin oxides , *ETCHING of silica , *CONTACT resistance (Materials science) - Abstract
In this letter, spray-coated single walled carbon nanotubes (SWNTs) as one of alternative electrodes in SnO thin-film transistors are demonstrated for emerging electronic applications. Herein, the device architecture of SnO TFTs with a polymer etch stop layer (SU-8) enables the selective etching of SWNTs in a desired region without the detrimental effects of SnO channel layers. Moreover, SnO TFTs with SWNT electrodes as substitutes successfully demonstrate decent width normalized electrical contact properties (∼1.49 kΩ cm), field effect mobility (∼0.69 cm2 V−1 s−1), sub-threshold slope (∼0.4 V dec−1), and current on–off ratio (Ion/Ioff ∼ 3.5 × 103). Systematic temperature dependency measurements elucidate that SnO channel transports with an activation energy within several tens of meV, together with decent contact resistance as compared to that of conventional Ni electrodes. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
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