Article
Nanoscience & Nanotechnology
Mari Napari, Tahmida N. Huq, David J. Meeth, Mikko J. Heikkil, Kham M. Niang, Han Wang, Tomi Iivonen, Haiyan Wang, Markku Leskela, Mikko Ritala, Andrew J. Flewitt, Robert L. Z. Hoye, Judith L. MacManus-Driscoll
Summary: High-performance p-type oxide thin film transistors (TFTs) have great potential for semiconductor applications, but often suffer from low hole mobility and high off-state currents. By applying a thin ALD Al2O3 passivation layer on the Cu2O channel and vacuum annealing, the TFT switching characteristics can be improved. Characterization by TEM-EDX and XPS shows that Al2O3 deposition on Cu2O reduces surface and forms a CuAlO2 interfacial layer. This, along with field-effect passivation, leads to improved TFT performance by reducing trap states and electron accumulation in the off-state.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Materials Science, Multidisciplinary
Song-Yi Ahn, Seong Cheol Jang, Aeran Song, Kwun-Bum Chung, Yong Joo Kim, Hyun-Suk Kim
Summary: The study found that SiOx passivation layer can reduce oxygen content, promote valence band delocalization of SnO semiconductor, and improve hole transport. Therefore, SnO TFTs with SiOx protective layer exhibit higher field-effect mobility compared to devices without passivation.
MATERIALS TODAY COMMUNICATIONS
(2021)
Article
Engineering, Electrical & Electronic
Jae Hak Lee, Jiyeon Kim, Minho Jin, Hyun-Jae Na, Haeyeon Lee, Changik Im, Youn Sang Kim
Summary: Cu2O TFTs with improved field-effect mobility and low off-current were achieved by reducing CuO impurities and dissociative Cu defects through a combination of deposition and annealing conditions. Nitrogen and oxygen play crucial roles in promoting Cu2O phase formation and preventing CuO phase formation.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Physics, Applied
Weidong Xu, Shiqi Yan, Xianjin Feng
Summary: High-performance InAlZnO (IAZO) Schottky barrier diodes (SBDs) with top Pd/IAZO Schottky contact were fabricated, with the 50 W-fabricated IAZO SBD exhibiting the best electrical properties, including a close-to-unity ideality factor, high rectification ratio, low series resistance, large barrier heights, and small barrier inhomogeneity. Additionally, the IAZO SBDs prepared at 50 W displayed the best device uniformity, highest reverse breakdown voltage, and fast response when applied to ultraviolet photodetection.
APPLIED PHYSICS LETTERS
(2021)
Review
Nanoscience & Nanotechnology
Hala A. Al-Jawhari
Summary: The development of high-performing p-type semiconductors is crucial for advancing transparent electronics, with copper oxide being a promising material due to its native p-type conductivity and abundance. The review discusses the progress in synthesis and deposition of solution-based CuxO thin films for thin-film transistors, emphasizing the growing efforts in low-temperature methods, nanoscale patterning, and green synthesis. Additionally, the use of nonoxide copper-based semiconductors for solution-processed TFTs will be explored.
ADVANCED ELECTRONIC MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Kishwar Mashooq, Jaesung Jo, Rebecca L. Peterson
Summary: This study presents the use of a floating metal cap layer and surface passivation to significantly improve the effective mobility and ON-OFF current ratio of p-type SnO TFTs. A record high p-type SnO TFT mobility of 19.1 cm(2)V(-1)s(-1) was achieved using a Ni/Au capping layer. The use of a bilayer TFT structure and appropriate surface passivation led to an approximately 8-fold improvement in the ON-OFF current ratio of SnO TFTs. Additionally, SnO bilayer TFTs exhibited more robust behavior to gate-bias stress compared to traditional SnO TFTs.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Computer Science, Hardware & Architecture
Se-Hyeong Lee, So-Young Bak, Chan-Yeong Park, Dongki Baek, Moonsuk Yi
Summary: This study aims to improve the electrical performance of amorphous oxide semiconductor (AOS) thin-film transistors (TFTs) by fabricating indium-zinc oxide (IZO) TFTs with HfO2/Al2O3 gate insulator deposited via low-temperature atomic layer deposition (ALD). The optimized TFTs showed significantly improved subthreshold swing, saturation carrier mobility, on-off current ratio, and threshold voltage shift compared to conventional samples.
Article
Engineering, Electrical & Electronic
Taeyoung Kim, Yoonsok Kim, Juntae Ahn, Eun Kyu Kim
Summary: The effect of barrier-controlled electrodes on the characteristics of amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) was studied by using an interlayer with modulated oxygen defects. Different resistivity interlayers of a-IGZO were controlled with various oxygen ratios during RF sputtering deposition. By inserting a-IGZO thin layers with different resistivities between the a-IGZO TFT channel and the source/drain electrodes, the threshold voltage, on/off ratio, subthreshold swing, and mobility of the devices were significantly improved.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Multidisciplinary Sciences
Qinqin Wang, Jian Tang, Xiaomei Li, Jinpeng Tian, Jing Liang, Na Li, Depeng Ji, Lede Xian, Yutuo Guo, Lu Li, Qinghua Zhang, Yanbang Chu, Zheng Wei, Yanchong Zhao, Luojun Du, Hua Yu, Xuedong Bai, Lin Gu, Kaihui Liu, Wei Yang, Rong Yang, Dongxia Shi, Guangyu Zhang
Summary: This article reports the successful growth of high-quality multi-layer MoS2 wafers via layer-by-layer epitaxy, and evaluates the atomic structures and electronic properties of wafers with different layer numbers. The study found significant improvements in device performances in thicker-layer MoS2 FETs, bringing practical applications of 2D MoS2 in electronics closer.
NATIONAL SCIENCE REVIEW
(2022)
Article
Chemistry, Multidisciplinary
Junhao Feng, Sang-Hwa Jeon, Jaehoon Park, Sin-Hyung Lee, Jaewon Jang, In Man Kang, Do-Kyung Kim, Jin-Hyuk Bae
Summary: In this study, a low-pressure thermal annealing (LPTA) treatment was used to improve the switching characteristics and bias stability of zinc-tin oxide (ZTO) thin film transistors (TFTs). The LPTA treatment reduced defects in the bulk, interface, and surface of the ZTO TFTs. The improved characteristics included a higher on/off ratio and subthreshold swing, as well as enhanced device-to-device uniformity.
Article
Engineering, Electrical & Electronic
Xing Yuan, Wei Dou, Yifan Wang, Jing Zeng, Liushun Wang, Liuhui Lei, Dongsheng Tang
Summary: This study demonstrates the use of copper iodide (CuI) as the channel layer in thin-film transistors (TFTs) to achieve NAND logic function for the first time. The optimization of TFTs through annealing and the replacement of standard silica gate dielectric with chitosan with electric-double-layer (EDL) effect result in improved performance. These p-type CuI TFTs have the potential to be used in complementary electronic circuits with low energy consumption and portable sensors.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Engineering, Electrical & Electronic
Kishwar Mashooq, Jaesung Jo, Rebecca L. Peterson
Summary: This study focuses on the performance issues of p-type tin monoxide thin-film transistors (TFTs) and establishes numerical models to extract and improve its defect state distribution, providing a theoretical basis for enhancing transistor performance.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Engineering, Electrical & Electronic
Fei Shan, Jae-Yun Lee, Gergely Tarsoly, Han-Lin Zhao, Xiao-Lin Wang, Tukhtaev Anvar, Suchang Yoo, Sung-Jin Kim
Summary: Solution processing is a promising method for fabricating transparent metal oxide layers, but there is a drawback of poor bias stability of the devices. In this study, postdeposition treatment of solution-processed indium oxide thin-film transistors was performed using a helical-focused plasma source. The best treatment conditions were found, and the oxide films were further studied using various techniques.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Chemistry, Physical
Dong-Gyu Kim, Su-Hwan Choi, Won-Bum Lee, Gyeong Min Jeong, Jihyun Koh, Seunghee Lee, Bongjin Kuh, Jin-Seong Park
Summary: This study proposes an atomic layer deposition (ALD)-derived Al2O3 gate insulator design for high-performance In-Ga-Zn-O thin-film transistors, achieved by controlling in situ plasma-enhanced ALD and thermal ALD processes. The optimal device demonstrates exceptionally high mobility, robust resistance to hydrogen annealing, and reliable positive bias temperature stress.
Article
Polymer Science
Zhengran He, Ziyang Zhang, Kyeiwaa Asare-Yeboah, Sheng Bi, Jihua Chen, Dawen Li
Summary: This study demonstrated the use of a metal-containing semicrystalline polymer as an additive to mediate the thin film morphology of solution-grown, small-molecule organic semiconductors, resulting in improved performance of organic thin film transistors.
Article
Materials Science, Multidisciplinary
Jeong Woo Park, Won-Gi Kim, Hyukjoon Yoo, Hyung Tae Kim, Dong Hyun Choi, Min Seong Kim, Hyun Jae Kim
Summary: A pulsed green laser was used to activate IGZO TFTs, achieving rapid and selective activation without conventional annealing. The activated IGZO TFTs demonstrated superior electrical characteristics compared to those annealed at 300 degrees C, showing potential for expanding applications in flexible and transparent devices.
JOURNAL OF INFORMATION DISPLAY
(2022)
Article
Chemistry, Physical
Byung Ha Kang, Kyungho Park, Mike Hambsch, Seongin Hong, Hyung Tae Kim, Dong Hyun Choi, Jin Hyeok Lee, Sunkook Kim, Hyun Jae Kim
Summary: Skin-conformable photoplethysmogram (PPG) sensors have been developed for continuous monitoring of heart rate and oxygen saturation, with features such as low power consumption, high reliability, and ease of operation. These sensors can operate separately at low and high heart rates, representing an innovative cardiovascular monitoring system that consumes less power and holds significance in the healthcare field.
Article
Materials Science, Multidisciplinary
Ki Woo Kim, Heesoo Lee, Hyun Jae Kim
Summary: This study proposes a new channel edge doping (CED) technique to reduce the hump effect in LTPS TFTs. By decreasing the electron concentration at the channel edge, the hump characteristic of LTPS TFTs can be effectively reduced. This technique is of great importance for manufacturing active-matrix organic light-emitting diode displays.
JOURNAL OF INFORMATION DISPLAY
(2022)
Article
Nanoscience & Nanotechnology
Ki Seok Kim, Min Seong Kim, Jusung Chung, Dongwoo Kim, I. Sak Lee, Hyun Jae Kim
Summary: We present a transparent and flexible polyimide (PI)-doped single-layer (PSL) phototransistor for visible light detection. By co-sputtering amorphous indium-gallium-zinc oxide (IGZO) and PI targets, the PSL is deposited on a SiO2 gate insulator, serving as both a channel layer and a visible-light absorption layer. The PI doping leads to improved optoelectronic characteristics, including higher photoresponsivity, photosensitivity, and specific detectivity, attributed to the induced subgap states. A flexible PSL phototransistor is also fabricated, demonstrating stable optoelectronic characteristics even after 10,000 bending tests.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Materials Science, Multidisciplinary
Zhangfu Chen, Woohyun Hwang, Minhyun Cho, Anh Tuan Hoang, Minju Kim, Dongwoo Kim, Dong Ha Kim, Young Duck Kim, Hyun Jae Kim, Jong-Hyun Ahn, Aloysius Soon, Heon-Jin Choi
Summary: This study reports on the growth of GeS microribbons via CVT, which exhibit low-symmetry orthorhombic structure and anisotropic optical and electronic properties. The GeS microribbons show photoluminescence and anisotropic absorption effects, making them suitable for photoelectronic transistors.
NPG ASIA MATERIALS
(2022)
Article
Multidisciplinary Sciences
Li Jin Kim, Sujin Jung, Hee Jun Kim, Bong Hwan Kim, Kyung Joon Kwon, Yong Min Ha, Hyun Jae Kim
Summary: In AMOLED displays, the image quality deteriorates when a variable refresh rate is applied and the frame rate changes. We experimentally demonstrated that this phenomenon is dependent on the frequency and can be prevented by applying a variable initial voltage. This approach promises to improve picture quality in AMOLED displays.
SCIENTIFIC REPORTS
(2022)
Article
Nanoscience & Nanotechnology
Gwan In Kim, Joohye Jung, Won Kyung Min, Min Seong Kim, Sujin Jung, Dong Hyun Choi, Jusung Chung, Hyun Jae Kim
Summary: This study proposes a plasma-polymerized hafnium oxide (HfOx) hybrid dielectric to achieve the synergistic advantages of outstanding flexibility in organic dielectrics and remarkable dielectric/insulating properties in inorganic dielectrics. By plasma-polymerizing high-k HfOx with polytetrafluoroethylene (PTFE), a flexible and hydrophobic fluoropolymer dielectric, the PPH-hybrid dielectric exhibits excellent flexibility and maintains a low leakage current density even after repetitive bending stress. The PPH-hybrid dielectric is also applied to amorphous indium-gallium-zinc oxide (IGZO) thin-film transistors (TFTs), demonstrating stable electrical performance and enhanced stability.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Editorial Material
Nanoscience & Nanotechnology
Gerald J. Meyer, Hyun Jae Kim
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Engineering, Electrical & Electronic
Jin Her, Won Kyung Min, Chul Sang Shin, Hoon Jeong, Jeong Ki Park, Hyun Jae Kim
Summary: We developed a new pixel circuit that utilizes dual-gate TFTs to compensate for threshold voltage variations and extend the input data range. Through simulations and experiments, we found that this new pixel circuit performs better in terms of sensing capability and current error rate. It is suitable for high-resolution AMOLED displays and can switch between G-Sync and S-Sync modes as needed.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Nanoscience & Nanotechnology
Kyung Min Kim, Jeong Suk Yang, Hyung Tae Kim, Inhyo Han, Sang-Hoon Jung, Joon-Young Yang, Yong Min Ha, Soo Young Yoon, Hyun Jae Kim
Summary: This study investigates the back-channel interface engineering of oxide thin-film transistors (TFTs) using commercially available silicon oxide (SiOx) and its effects on the electrical characteristics of fully integrated TFTs. The proposed method effectively alleviates back-channel damage, promotes oxygen inter-diffusion, suppresses excess hydrogen inflow, and boosts out-diffusion of residual copper. The result is improved device uniformity and electrical characteristics, including high field effect mobility and significantly suppressed threshold voltage variation with decreasing channel length.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Won Kyung Min, Chihyeong Won, Dong Hyun Kim, Sanghyeon Lee, Jusung Chung, Sungjoon Cho, Taeyoon Lee, Hyun Jae Kim
Summary: A negatively responsive switch-type strain-sensor with twisted conductive fibers is developed that can significantly increase its conductivity from insulating to conducting properties. This sensor can regulate the mutual contact resistance under tensile strain while maintaining exceptional durability. Additionally, three healthcare monitoring systems with near-zero standby power are also developed, expanding the utilization range of fiber strain-sensors.
ADVANCED MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Jung Chul Kim, I. Sak Lee, Hyung Tae Kim, Jong Bin An, Jae Sung Kim, Juhn Suk Yoo, Han Wook Hwang, Hyun Chul Choi, Yong Min Ha, Hyun Jae Kim
Summary: This paper presents a new pixel circuit and driving scheme for mobile devices with AMOLED displays, utilizing LTPO TFTs. The proposed circuit and scheme ensure uniform luminance and eliminate flickering at various refresh rates. Experimental results demonstrate that extending the compensation time and applying a higher voltage to the D-TFTs effectively improve luminance uniformity and reduce flicker. A 6.0-inch QHD LTPO-based AMOLED display was successfully fabricated using this approach.
JOURNAL OF INFORMATION DISPLAY
(2023)
Editorial Material
Engineering, Electrical & Electronic
Hyun Jae Kim, Kirk Schanze, Chengmei Zhong
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Bogyeom Seo, Jusung Chung, Naresh Eedugurala, Jason D. Azoulay, Hyun Jae Kim, Tse Nga Ng
Summary: This study demonstrates the integration of an organic bulk heterojunction polymer layer on an oxide thin-film transistor to achieve high-efficiency photodetection in the short-wave infrared region. By using trap-assisted charge injection, the organic semiconductor's photoresponse at longer wavelengths is enhanced. The detector performance is optimized by investigating the balance between bias stress and signal-to-noise under different bias conditions, resulting in a responsivity at 1550 nm up to 130 mA/W at a low light intensity.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Seung Hee Kang, I. Sak Lee, Kyungmoon Kwak, Kyeong Take Min, Nack Bong Choi, Han Wook Hwang, Hyun Chul Choi, Hyun Jae Kim
Summary: The effect of boron (B) implantation into the source/drain region of a self-aligned coplanar amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistor (TFT) on the electrical properties and device stability was investigated. The results showed that the electrical properties were optimized when the projection range of B was in the central vertical region of the film. B implantation decreased resistivity and improved field-effect mobility, and the fabricated TFTs exhibited excellent stability.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
