Article
Engineering, Electrical & Electronic
Jiangwei Liu, Tokuyuki Teraji, Bo Da, Yasuo Koide
Summary: The electrical properties and thermal stabilities of boron-doped diamond (B-diamond) MOS capacitor and MOS field-effect transistor (MOSFET) on a flat diamond epitaxial layer were investigated after annealing at 500 degrees C. The annealing process slightly increased the leakage current density of the B-diamond MOS capacitor. The drain-current and extrinsic transconductance maxima of the MOSFETs also showed improvements after annealing compared to the as-fabricated state. These results are significantly better than previously reported B-diamond MOSFETs.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Chemistry, Multidisciplinary
Yu-Chieh Chien, Xuewei Feng, Li Chen, Kai-Chun Chang, Wee Chong Tan, Sifan Li, Li Huang, Kah-Wee Ang
Summary: A universal and simple method has been developed in this study to accurately extract critical parameters in 2D FETs, including characteristic temperature (T-o), threshold voltage (V-T), R-SD, and mu(int), and the practicality of this method is extensively explored by characterizing the temperature-dependent carrier transport behavior and strain-induced band structure modification in 2D semiconductors.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Xiaotong Zhao, Jie Liu, Haiyang Li, Jiajun Zhang, Chunlei Li, Yicai Dong, Xiaosong Shi, Yanan Sun, Ji Liu, Ming Lei, Lang Jiang
Summary: Monolayer molecular crystals (MMCs) have aroused global research interest due to their unique properties. Compared with their bulk counterparts, MMCs have lower contact resistance, making them ideal carriers for studying the intrinsic properties of organic semiconductors. However, studies on anisotropic charge transport in MMCs are still rare. In this study, by non-destructively preparing electrodes on MMCs, anisotropic charge transport properties of two typical MMCs were obtained, providing a basis for realizing high performance device arrays with low device-to-device variation.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Chemistry, Multidisciplinary
Jiamin Sun, Xinming Zhuang, Yibo Fan, Shuai Guo, Zichao Cheng, Dong Liu, Yanxue Yin, Yufeng Tian, Zhiyong Pang, Zhipeng Wei, Xiufeng Song, Lei Liao, Feng Chen, Johnny C. Ho, Zai-xing Yang
Summary: In this research, an efficient strategy using metal-semiconductor junction to enhance the hole mobility of p-channel devices was proposed. By depositing CMOS-compatible metals on the surface of GaSb nanowire field-effect transistors, the peak hole mobility was increased threefold. This approach was also effective for other p-channel devices like GaAs and WSe2, resulting in improved performance for CMOS inverters.
Article
Physics, Applied
I. U. Jayawardhena, R. P. Ramamurthy, D. Morisette, A. C. Ahyi, R. Thorpe, M. A. Kuroda, L. C. Feldman, S. Dhar
Summary: Silicon carbide (4H) based metal-oxide-semiconductor field-effect transistors offer capabilities in high power and high temperature that silicon cannot achieve. This research investigates the use of deposited Al2O3 dielectrics instead of thermal oxidation, resulting in improved electronic properties. The optimal structure involves preparation of a nitrided surface through NO annealing, hydrogen exposure, and Al2O3 deposition, leading to high inversion layer field-effect mobilities. Leakage currents and interface breakdown are also observed in various Al2O3/4H-SiC MOS structures.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Kjell Jeppson
Summary: Graphene field-effect transistors (GFETs) have been used extensively for device characterization, and recently the focus has shifted to the methods for device characterization themselves. This article presents a structured methodology for extracting and validating GFET model parameter values based on the physics of FETs and GFETs. The extraction process divides the GFET resistance into a constant part believed to represent the series/contact resistance and a gate-voltage-dependent part that contains first-order information about mobility degradation. The main influence of quantum capacitance can be captured by an equivalent oxide thickness (EOT) instead of the insulator thickness.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Chemistry, Physical
Xiaoqiao Ma, Bin He, Jinrui Guo, Jiale Han, Wenqi Gao, Jiaqing Wang, Yue Han, Hong Fang, Weiming Lu
Summary: In this study, a transistor composed of graphene and PZT was fabricated, and it was found that applying voltage to PZT can result in hysteresis in the graphene transport curve, thus tuning the conductivity of graphene. This provides a new strategy for designing electronic devices based on 2D materials.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Polymer Science
Lingli Zhao, Yanyan Cao, Hanwen Qin, Xi He, Zhiyuan Zhao, Yunlong Guo, Huajie Chen
Summary: We report the synthesis and characterization of a core-extended acceptor building block, 2,7-dibromobenzo[2,1-b:3,4-b ']dithiophene diimides (abbreviated as 2Br-NTI), which achieves high electron affinity and tunable solubility. By embedding the acceptor and electron-rich species into polymer backbones, the resulting conjugated copolymers exhibit near-linearly pi-extended conjugation and intriguing photophysical/electrochemical properties.
Article
Multidisciplinary Sciences
Yuan Liu, Xidong Duan, Hyeon-Jin Shin, Seongjun Park, Yu Huang, Xiangfeng Duan
Summary: The article reviews the promise and current status of 2D transistors, emphasizing the potential misestimation or misinterpretation of widely used device parameters. It suggests using more reliable methods to assess the potential of diverse 2D semiconductors and highlights key technical challenges in optimizing the performance of 2D transistors.
Article
Materials Science, Multidisciplinary
Patrik Olausson, Lasse Sodergren, Mattias Borg, Erik Lind
Summary: An optimized process flow for near-surface quantum well metal-oxide-semiconductor field-effect transistors (MOSFETs) based on MOVPE-grown InxGa1-xAs layers is presented, showing significant enhancement in MOS structure quality through optimized pre-growth cleaning and post-metal anneal. This optimization marks a first step towards a scalable platform for topological qubits utilizing a well-defined network of lateral InxGa1-xAs nanowires grown by selective area growth.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2021)
Article
Physics, Applied
Koji Ito, Masahiro Horita, Jun Suda, Tsunenobu Kimoto
Summary: Hall effect measurements were performed on MOSFETs with and without post-oxidation-annealing (POA) to study the effect of trapped electrons. MOSFETs annealed in phosphoryl chloride exhibited higher Hall mobility in the high effective normal field region compared to MOSFETs annealed in nitric oxide, indicating that trapped electrons act as strong Coulomb scattering centers for the latter.
APPLIED PHYSICS EXPRESS
(2023)
Article
Multidisciplinary Sciences
Mantian Xue, Charles Mackin, Wei-Hung Weng, Jiadi Zhu, Yiyue Luo, Shao-Xiong Lennon Luo, Ang-Yu Lu, Marek Hempel, Elaine McVay, Jing Kong, Tomas Palacios
Summary: Two-dimensional materials such as graphene have great potential as biosensors, but are limited by device-to-device variation. In this study, a robust bioelectronic sensing platform is developed to overcome these challenges, achieving rapid, portable, and reliable measurements. The platform exhibits reconfigurable multi-ion electrolyte sensing capability and provides highly sensitive, reversible, and real-time response for various ions in complex solutions.
NATURE COMMUNICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Zhihui Cheng, Chin-Sheng Pang, Peiqi Wang, Son T. Le, Yanqing Wu, Davood Shahrjerdi, Iuliana Radu, Max C. Lemme, Lian-Mao Peng, Xiangfeng Duan, Zhihong Chen, Joerg Appenzeller, Steven J. Koester, Eric Pop, Aaron D. Franklin, Curt A. Richter
Summary: This study proposes guidelines for reporting and benchmarking the parameters and performance of field-effect transistors, addressing challenges in device performance assessment and offering a more consistent and meaningful approach for the field to progress.
NATURE ELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
Gard Lyng Rodal, Dimosthenis Peftitsis
Summary: This article presents a novel current-source gate driver for SiC MOSFETS with adaptive functionalities. The proposed driver aims to decouple and improve controllability of di/dt, dv/dt, as well as decrease turn-ON and turn-OFF delay times compared to conventional gate drivers. The performance of the proposed driver is validated experimentally, showing significant reduction in delay times and improved controllability.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2023)
Article
Materials Science, Coatings & Films
Gilles Delie, Peter M. M. Litwin, Gaby C. C. Abad, Stephen J. J. McDonnell, Daniele Chiappe, Valeri V. V. Afanasiev
Summary: Internal photoemission was used to determine the energy position of the top valence band of mono- and few-layer WS2 on SiO2/Si substrate. Contrary to density functional theory calculations, it was found that the valence band top in WS2 shifts up in energy with decreasing number of monolayers. The band alignment of WS2 with SiO2 appears to be less sensitive to the WS2 synthesis route compared to the MoS2/SiO2 interface.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2022)
Article
Chemistry, Multidisciplinary
Hongyue Jing, Hyeonwoo Yeo, Benzheng Lyu, Junga Ryou, Seunghyuk Choi, Jin-Hong Park, Byoung Hun Lee, Yong-Hoon Kim, Sungjoo Lee
Summary: The paper demonstrates the chemical modification of Ti3C2Tx MXene via diazonium covalent chemistry and the subsequent effects on the electrical properties of MXene. The work function of functionalized MXene can be modulated by adjusting the concentration of the diazonium salt solution, with an adjustable range of around 0.6 eV. The controlled modification of surface groups in Ti3C2Tx may imbue Ti3C2Tx with favorable electronic behaviors, showing prospects for electronic field applications.
Article
Nanoscience & Nanotechnology
Myungwoo Son, Jaewon Jang, Yongsu Lee, Jungtae Nam, Jun Yeon Hwang, In S. Kim, Byoung Hun Lee, Moon-Ho Ham, Sang-Soo Chee
Summary: The study demonstrates the fabrication of a Cu-graphene heterostructure interconnect by synthesizing graphene directly on a Cu interconnect, resulting in enhanced electrical properties and reliability compared to pure Cu interconnects. The doping of graphene to increase carrier density significantly improves the reliability of the graphene-capped interconnect, showing compatibility with practical applications such as next-generation interconnect materials in CMOS back-end-of-line (BEOL).
NPJ 2D MATERIALS AND APPLICATIONS
(2021)
Article
Chemistry, Physical
Seung-Mo Kim, Ho-In Lee, Yongsu Lee, So-Young Kim, Tae Jin Yoo, Sunwoo Heo, Soo Cheol Kang, Hyeon Jun Hwang, Byoung Hun Lee
Summary: A new non-destructive defect analysis method AMDCA was reported to assess the defect density and energy levels in graphene and other two-dimensional materials. The method was validated by observing charge trap densities in a graphene field-effect transistor experiment. This method can be valuable for studying graphene devices and other 2D materials without body contacts.
Article
Optics
Tae Jin Yoo, So-Young Kim, Min Gyu Kwon, Cihyun Kim, Kyoung Eun Chang, Hyeon Jun Hwang, Byoung Hun Lee
Summary: In this study, simultaneous optimization of detectivity and dark current in a graphene/p-type silicon photodetector was achieved by modulating the Schottky barrier height through doping graphene with polyethyleneimine (PEI). Doping graphene with PEI resulted in a three orders of magnitude reduction in dark current and a 529% improvement in detectivity at 850 nm compared to undoped graphene/p-type silicon photodetectors. These results highlight the effectiveness of chemical doping of graphene as a simple and efficient approach to enhance the detectivity of heterojunction photodetectors.
LASER & PHOTONICS REVIEWS
(2021)
Article
Materials Science, Multidisciplinary
So-Young Kim, Jiae Yoo, Hyeon Jun Hwang, Byoung Hun Lee
Summary: The study demonstrated a universal ternary device that can be programmed into n-type and p-type ternary devices, and showed the feasibility of a standard ternary inverter function through discretely programmed graphene channels. The concept of programmable ternary logic, based on channel width modulation and ferroelectric doping, is valuable for future experimental studies on multi-valued logic architecture.
ORGANIC ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Ho-In Lee, So-Young Kim, Seung-Mo Kim, Yongsu Lee, Hae-Won Lee, Sung Ho Yu, Hyeon Jun Hwang, Myung Mo Sung, Byoung Hun Lee
Summary: This work investigates the scaling prospect of ZnO stacked nanosheet channel ternary field effect transistor, as well as the impact of scaling geometric parameters on its performance. The results show that compared to other ternary logic devices, this device has lower power consumption and higher noise margin in the intermediate state. The feasibility for stable ternary circuit operation is also confirmed.
IEEE ELECTRON DEVICE LETTERS
(2022)
Article
Optics
Jaecheol Cho, Sungsam Kang, Byeongha Lee, Jungho Moon, Yong-Sik Lim, Mooseok Jang, Wonshik Choi
Summary: This study presents a method to separately quantify ballistic and multiple-scattered waves, even in the presence of strong multiple scattering interference, and analyze their temporal behavior, laying a foundation for utilizing multiple-scattered waves for deep-tissue imaging.
Article
Chemistry, Multidisciplinary
Asif Ali, So-Young Kim, Muhammad Hussain, Syed Hassan Abbas Jaffery, Ghulam Dastgeer, Sajjad Hussain, Bach Thi Phuong Anh, Jonghwa Eom, Byoung Hun Lee, Jongwan Jung
Summary: The electronic properties of single-layer, CVD-grown graphene were affected by deep ultraviolet (DUV) light irradiation in different radiation environments, leading to p-type or n-type doping. The degree of doping increased with exposure time, with n-type doping in vacuum reaching saturation after 60 minutes. Additionally, p-type doping in air exhibited higher stability, while n-type doping in nitrogen gas was relatively unstable over time.
Article
Nanoscience & Nanotechnology
Cihyun Kim, Tae Jin Yoo, Min Gyu Kwon, Kyoung Eun Chang, Hyeon Jun Hwang, Byoung Hun Lee
Summary: The structure of a gate-controlled graphene/germanium hybrid photodetector was optimized by splitting the active region, resulting in significantly improved infrared detection capability.
Article
Optics
Min Gyu Kwon, Cihyun Kim, Kyoung Eun Chang, Tae Jin Yoo, So-Young Kim, Hyeon Jun Hwang, Sanghan Lee, Byoung Hun Lee
Summary: In this paper, we improved the performance of a near-infrared graphene/germanium heterojunction photodetector by doping graphene with p-type chemical, which lowered the Fermi level and increased the Schottky barrier. The responsivity and detectivity were significantly improved, making it valuable for the development of graphene/semiconductor based photodetectors and near-infrared sensors.
Article
Chemistry, Analytical
Myeongseop Kim, Bobae Cho, Hansol Lee, Taeil Yoon, Byeongha Lee
Summary: In this study, a hemispherical resonator gyroscope (HRG) was implemented using a consumer wineglass as the resonator and 3 x 3 optical interferometers as the detectors. The low quality of the off-the-shelf wineglass as a resonator was overcome by the high performance of the optical interferometer. The asymmetries in stiffness and absorption of the resonator were analyzed theoretically and confirmed experimentally. The straightness of the amplitude ratio of two n = 2 fundamental resonant modes of the resonator in a complex plane was proven. By utilizing this straightness and the high performance of the optical interferometer, four real constant parameters characterizing the HRG system were extracted. Experimental results showed that it was possible to measure the Coriolis force at the level of industrial grade using a resonator with an average resonance frequency of 444 Hz and Q value of 1477.2, and achieve a small bias stability of 2.093 degrees/h.
Article
Materials Science, Multidisciplinary
Soo Cheol Kang, Hyun-Wook Jung, Sung-Jae Chang, Ilgyu Choi, Sang Kyung Lee, Seung Mo Kim, Byoung Hun Lee, Ho-Kyun Ahn, Jong -Won Lim
Summary: AlGaN/GaN MIS-HEMTs fabricated with a recess gate exhibit sensitivity to changes in the polarity of the gate voltage. Under negative gate bias stress, electron detrapping requires overcoming an energy barrier, leading to increased temperature dependence. Degradation occurs primarily at the Al2O3/AlGaN interface rather than in the channel or mobility. During relaxation, the time exponent of V-T shift is relatively low, which may be attributed to further degradation at the broader energy levels of the Al2O3/AlGaN interface.
CURRENT APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Hyeon Jun Hwang, So-Young Kim, Sang Kyung Lee, Byoung Hun Lee
Summary: This study investigated the performance of a thermoelectric device made of centimeter-scale monolayer graphene. The carrier type and junction profile of the active graphene layer were modified through chemical doping. After device optimization, improvements in carrier concentration of at least 200% and enhancements in power factor of at least 600% were achieved. Under optimal conditions, a maximum Seebeck coefficient of -350 mu V/K and power factor of -14000 mu W/mK^2 were obtained, which are at least three times higher than the best values reported for other graphene-based thermoelectric devices.
Article
Chemistry, Multidisciplinary
Hyeon Jun Hwang, So-Young Kim, Sang Kyung Lee, Byoung Hun Lee
Summary: By modifying the Fermi level of large-area graphene using an external electric field, researchers have experimentally investigated a reconfigurable passive device that can manipulate its resonant frequency by controlling its quantum capacitance value without complicated equipment. When the total capacitance change caused by the gate bias increased to 60% compared to the initial state, a 6% shift in the resonant frequency could be achieved. Although the signal characteristics of the graphene antenna are slightly inferior to conventional metal antennas, simplifying the device structure allows reconfigurable characteristics to be implemented using only the gate bias change.
Article
Engineering, Electrical & Electronic
Tae Jin Yoo, Hyeon Jun Hwang, Soo Cheol Kang, Sunwoo Heo, Ho-In Lee, Young Gon Lee, Hokyung Park, Byoung Hun Lee
Summary: Barrier height, trap state, bandgap, and band alignment information of the metal-ZrO2-metal capacitor were extracted using internal photoemission (IPE) system. By correlating the IPE analysis with I-V and C-V characteristics before and after rapid thermal annealing, the origin and transformation of defect states were successfully investigated. The analysis revealed that deep-level defects originating from oxygen vacancies near the top electrode are the cause of leakage current in MIM capacitor, which can be effectively reduced by proper thermal annealing.
IEEE JOURNAL OF THE ELECTRON DEVICES SOCIETY
(2021)
