Article
Chemistry, Multidisciplinary
Junhwan Choi, Chungryeol Lee, Juyeon Kang, Changhyeon Lee, Seung Min Lee, Jungyeop Oh, Sung-Yool Choi, Sung Gap Im
Summary: This paper presents a universal strategy to synthesize high-k hybrid dielectric materials by incorporating a high-k polymer layer on top of various inorganic layers generated by different fabrication methods. These hybrid dielectric materials have high capacitance and excellent insulating properties, and can achieve stable operation at ultralow voltages.
Article
Chemistry, Multidisciplinary
Qingqing Cheng, Shuai Yang, Cehuang Fu, Liangliang Zou, Zhiqing Zou, Zheng Jiang, Junliang Zhang, Hui Yang
Summary: A cobalt oxide aided structural evolution strategy was presented to controllably synthesize high-loaded Pt1Co1 intermetallic compounds with enhanced ORR activity and durability. The ordered arrangement of Pt-Co atoms endowed surface Pt with a lowered d band centre and enhanced oxidation resistance of Pt/Co sites, boosting both ORR activity and durability simultaneously. The optimized catalyst exhibited record-high power density and exceeded the DOE target, confirming the superiority of high-loaded Pt1Co1 intermetallic compounds in activity expression under fuel cell conditions.
ENERGY & ENVIRONMENTAL SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Fei Yang, Yian Wang, Yingdan Cui, Xuming Yang, Yuanmin Zhu, Catherine M. Weiss, Menghao Li, Guangyu Chen, Yushan Yan, M. Danny Gu, Minhua Shao
Summary: This study synthesized sub-3 nm Pt@Ru core-shell nanoparticles using the impregnation method, which showed high electrocatalytic activity and peak power density. The electron transfer from the Ru shell to the Pt core and the contribution of ultrafine particles were found to be responsible for the improved performance.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Materials Science, Multidisciplinary
Qing Gong, Hong Zhang, Haoran Yu, Sungho Jeon, Yang Ren, Zhenzhen Yang, Cheng-Jun Sun, Eric A. Stach, Alexandre C. Foucher, Yikang Yu, Matthew Smart, Gabriel M. Filippelli, David A. Cullen, Ping Liu, Jian Xie
Summary: Researchers have developed a simple method to deposit sub-3-nm L10-PtM nanoparticles onto carbon supports, resulting in improved Pt utilization and mass transport in polymer electrolyte membrane fuel cells. This approach achieved excellent oxygen reduction reaction activity, high power density, and durability, meeting the targets set by the Department of Energy.
Article
Engineering, Electrical & Electronic
Liting Liu, Lingan Kong, Qianyuan Li, Chenglin He, Liwang Ren, Quanyang Tao, Xiangdong Yang, Jun Lin, Bei Zhao, Zhiwei Li, Yang Chen, Wanying Li, Wenjing Song, Zheyi Lu, Guoli Li, Siyu Li, Xidong Duan, Anlian Pan, Lei Liao, Yuan Liu
Summary: Vertical transistors using molybdenum disulfide with channel lengths down to one atomic layer can be created with a high-quality metal-semiconductor interface through a mechanical van der Waals transfer process.
NATURE ELECTRONICS
(2021)
Article
Nanoscience & Nanotechnology
Nikolaos Farmakidis, Jacob L. Swett, Nathan Youngblood, Xuan Li, Charalambos Evangeli, Samarth Aggarwal, Jan A. Mol, Harish Bhaskaran
Summary: Nanocalligraphy scanning probe lithography (nc-SPL) overcomes the limitations of conventional scanning probe lithography by achieving real-time adjustment of structures at the micron to nanometer scales, improving throughput, tip longevity, and reliability, and can be applied in both positive and negative tone patterning modes.
MICROSYSTEMS & NANOENGINEERING
(2021)
Article
Materials Science, Multidisciplinary
Yunqin Hu, Linlin Xiang, Long Kuai, Yanyan Zhao, Sufeng Cao, Li Liu, Caihong Fang, Baoyou Geng
Summary: This research establishes a new method of incipient wetness impregnation (IWI) for preparing high-loading Pt/C catalysts with sub-3 nm Pt nanoparticles and a loading up to 60 wt%. A two-step reduction strategy is developed to overcome the limitations of traditional IWI method in controlling the size of Pt nanoparticles at high loadings. The as-prepared 60% Pt/C catalyst exhibits high power density and low Pt loading, outperforming the state-of-the-art commercial 60% Pt/C in H-2-air fuel cells.
ACS MATERIALS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Wei Li, Jinlei Wei, Wen Chen, Sicheng Jing, Jinghua Pan, Baoan Bian, Bin Liao, Guoliang Wang
Summary: The performance of black phosphorous field-effect transistors with different contacts was investigated using quantum transport calculations, with the double-gated model showing significant improvements. Borophene contacts met 10-70% of HP standards, while graphene contacts far exceeded them.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2022)
Article
Engineering, Electrical & Electronic
Yanxia Lin, Yu Cao, Sujuan Ding, Panpan Zhang, Lin Xu, Chenchen Liu, Qianlan Hu, Chuanhong Jin, Lian-Mao Peng, Zhiyong Zhang
Summary: Aligned semiconducting carbon nanotubes have the potential to be an alternative to silicon in scaled field-effect transistors (FETs) due to their easy miniaturization and high energy efficiency. Researchers have successfully fabricated aligned carbon nanotube FETs at the same dimensions as low-node silicon technology, demonstrating size and electronic performance superior to silicon transistors. By introducing a full-contact structure, nanotube FETs with scaled contacted gate pitch comparable to the 10 nm silicon technology node have been created, exhibiting higher carrier mobility and Fermi velocity.
NATURE ELECTRONICS
(2023)
Article
Chemistry, Multidisciplinary
Tandra Ghoshal, Nadezda Prochukhan, Michael A. Morris
Summary: This study utilized a low-cost block copolymer (BCP) approach to create a range of well-ordered inorganic and dielectric nanoparticles and nanowire array patterns on substrates. Through optimization of solvent annealing parameters and calibration of precursor solution concentrations, high-quality nanoparticles and nanowires were achieved.
Article
Chemistry, Multidisciplinary
Maritza Mujica, Amar Mohabir, Pralav P. Shetty, Wesley R. Cline, Daniel Aziz, Matthew T. McDowell, Victor Breedveld, Sven Holger Behrens, Michael A. Filler
Summary: In this study, we demonstrate the growth of single-crystalline i-Si, i-Si/n-Si, and SixGe1-x/SiyGe1-y nanowires via the Geode process. The use of microcapsules improves scalability while maintaining programmability of the nanowires. Heat and mass transport limitations introduced by the microcapsule wall are shown to be negligible, allowing for consistent compositional control. The efficient transport also minimizes structural variations in nanowires grown in microcapsules with different sizes and wall thicknesses.
Article
Materials Science, Multidisciplinary
Chen Wu, Xudong Fang, Qiang Kang, Ziyan Fang, Hao Sun, Dong Zhang, Libo Zhao, Bian Tian, Ryutaro Maeda, Zhuangde Jiang
Summary: SiC, as a third generation semiconductor, is widely used in power devices and sensors. The formation mechanism and high temperature resistance of ohmic contacts, an important component for signal output of SiC chips, have been investigated. It is found that the contact metal determines the formation of ohmic contact. The incorporation of barrier and protective layers can improve the high temperature stability of the contacts. The stable and high temperature ohmic contact can be applied in various SiC devices.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Engineering, Electrical & Electronic
V. Bharath Sreenivasulu, Vadthiya Narendar
Summary: This study explores silicon ultrathin junctionless n-FinFET with L-G=3 nm and 1 nm by using high-k gate dielectric based on HfxTi1-xO2 for the first time. The performance of the 3D devices is analyzed using self-consistent Poisson and Schrodinger equations based on a non-equilibrium Green's function approach. The results show that silicon channel can be a viable option for future technology nodes as long as spacer dielectrics are driven with optimized techniques. The study also demonstrates performance improvement in ultra-short length devices by inducing single-k, dual-k, and hybrid spacers.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2022)
Article
Energy & Fuels
Christoph Luderer, Dilara Kurt, Anamaria Moldovan, Martin Hermle, Martin Bivour
Summary: In this study, the intrinsic hydrogenated amorphous silicon layer in silicon heterojunction solar cells was modified to improve carrier transport while maintaining excellent passivation of the silicon absorber surface. The microstructure of different multilayer intrinsic silicon films was measured and its influence on contact resistance and passivation quality was investigated. The results showed that there is a trade-off between passivation and transport, which is determined by the properties of the amorphous silicon layer close to the silicon surface. Modified intrinsic layers were tested on cell level and showed reduced series resistance and increased fill factor, leading to improved power conversion efficiency. Additionally, the beneficial effect of a hydrogen plasma treatment on passivation and transport of the hole contact was demonstrated at the device level.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2022)
Article
Chemistry, Multidisciplinary
Yuki Akanuma, Takane Imaoka, Hiroyasu Sato, Kimihisa Yamamoto
Summary: Controversy surrounds the roles of metal core and shell in photoluminescence of ligand-protected metal nanoclusters. The inclusion of silver ions in a platinum-thiolate complex led to a significant increase in photoluminescent quantum yield. DFT calculations showed that LUMO, with contributions from Ag s-orbital and Pt d-orbitals, played a critical role in suppressing structural distortion in the excited state.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Engineering, Electrical & Electronic
Amitabha Nath, Bikram Kishore Mahajan, Laishram Robindro Singh, Shubhajit Vishwas, Rajib Kumar Nanda, Mitra Barun Sarkar
Summary: In2O3 vertical nanostructures were fabricated using a GLAD technique on an In2O3 thin film deposited on an n-type silicon substrate. The structures showed enhanced absorption and photodetection, likely due to the presence of surface-related trap states or oxygen vacancies. The device exhibited improved photosensitivity and detectivity compared to a bare In2O3 thin film device.
JOURNAL OF ELECTRONIC MATERIALS
(2021)
Article
Physics, Applied
Yen-Pu Chen, Bikram K. Mahajan, Dhanoop Varghese, Srikanth Krishnan, Vijay Reddy, Muhammad A. Alam
Summary: Unlike traditional logic transistors, hot carrier degradation in power transistors involves simultaneous and potentially correlated degradation in multiple regions. Understanding and characterizing the voltage- and temperature-dependence of these region-specific degradations is crucial for developing predictive HCD models. This Letter presents a new three-point I-V spectroscopy technique using a physics-based tandem-FET model to extract mobility and threshold voltage degradations in the channel and drift regions of an LDMOS transistor, which could be generalized to other LDMOS transistor configurations.
APPLIED PHYSICS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Bikram Kishore Mahajan, Yen-Pu Chen, Muhammad Ashraful Alam
Summary: This article investigates the physical origin of anomalous HCD degradation in power transistors and proposes a general principle to restore the universality of degradation kinetics. The study finds that the empirical models used to evaluate HCD degradation in power transistors can be considered as approximations of the generalized approach.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Engineering, Electrical & Electronic
Ratul K. Baruah, Bikram K. Mahajan, Yen-Pu Chen, Roy P. Paily
Summary: Silicon carbide is chosen for harsh environment applications due to its high critical electric field and radiation tolerance. Junctionless transistors show better performance than conventional MOSFETs at high temperatures.
JOURNAL OF ELECTRONIC MATERIALS
(2021)
Article
Chemistry, Physical
Amitabha Nath, Naveen Bhati, Bikram Kishore Mahajan, Jayanta Kumar Rakshit, Mitra Barun Sarkar
Summary: This report outlines the fabrication of Ag nanoparticles on In2O3/TiO2 thin film using the SS-GLAD technique, with a subsequent detailed analysis of the improved electrical and optical properties compared to the thin film without Ag nanoparticles. The inclusion of Ag nanoparticles led to a reduction in bandgap energy, higher transmittance, lower reflectance, and increased power conversion efficiency, suggesting promising potential for photovoltaic applications.
Article
Engineering, Electrical & Electronic
Amitabha Nath, Bikram Kishore Mahajan, Aniruddha Mondal, Laishram Robindro Singh, Mitra Barun Sarkar
Summary: This paper studies the impact of a high-performance nanostructured device using metal nanoparticle (NP) deposition, with a focus on an Ag NP coated In2O3 nanostructured device. Through analysis of morphology, crystal structures, and electrical characteristics, it was found that the Ag NP coated device exhibited improved conductance and trap states, making it suitable for various applications such as catalysts and medical devices.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(2021)
Article
Engineering, Electrical & Electronic
Yen-Pu Chen, Mengwei Si, Bikram Kishore Mahajan, Zehao Lin, Peide D. Ye, Muhammad Ashraful Alam
Summary: Recently, BEOL compatible In2O3 thin-film transistors grown by ALD have achieved high drain current and small threshold voltage shift under stress conditions. The reliability issues of PBTS and HCD, characterized by a two-stage threshold voltage shift, are attributed to electron trapping/trap-generation and hydrogen-assisted formation of donor-traps. The correlation between HCD and PBTS in BEOL-TFTs is due to the stronger vertical field in an ultrathin device.
IEEE ELECTRON DEVICE LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Bikram Kishore Mahajan, Yen-Pu Chen, Nicolo Zagni, Muhammad Ashraful Alam
Summary: This paper discusses the importance of developing unified principles to guide the development of wide bandgap semiconductors, proposing a comprehensive intrinsic safe operating area that optimizes trade-offs in advance. By comparing its predictions with experimental data, it provides a new perspective for evaluating the performance of power electronic devices.
IEEE TRANSACTIONS ON DEVICE AND MATERIALS RELIABILITY
(2021)
Article
Crystallography
Debajit Deb, Bikram Kishore Mahajan
Summary: In this study, modeling of phonon and defect-induced spin relaxation length (L-S) in Fe3O4 and organic semiconductor (OSC) Alq(3) has been demonstrated. The results show that L-S of Alq(3) decreases with enhanced disorder and film thickness at a low film width regime. An exponential change of L-S at low width regime is found for Alq(3) but not for Fe3O4, indicating comparable spin-dependent scattering and L-S in Fe3O4. L-S also decreases with spin-flip probability for both Alq(3) and Fe3O4. Voltage-dependent tunnel magnetoresistance (TMR) response in Fe3O4/Alq(3)/Co and LSMO/Alq(3)/Co hybrid magnetic tunnel junction (MTJ) devices is attributed to modified spin filter effect across magnetic/OSC junction at high bias regime. TMR reduction with Alq(3) thickness for Fe3O4 device is attributed to spin relaxation at the organic spacer layer. A low bias peak from differential TMR indicates spin-polarized injection for both MTJ devices. Enhanced in-plane spin transfer torque for both MTJ devices is associated with modified spin filtering at magnetic/OSC junctions. Lower TMR signal for LSMO device indicates reduced tunneling and enhanced carrier injection across the OSC, which is also supported by the band structure profile. The TMR response observed from simulation results matches well with previously reported experimental results. Higher TMR response for Fe3O4 device indicates the possibility of device employment in room temperature magnetic recording applications.
Article
Engineering, Electrical & Electronic
Ratul Kumar Baruah, Bikram Kishore Mahajan, Sujay Routh
Summary: In this study, a double-gate junctionless SiC FET with an embedded P+ pocket in the oxide layer (P+-SiCJLT) is investigated for high-temperature and high-voltage applications. The P+-SiCJLT exhibits better performance compared to a device of similar dimensions without the P+ layer (SiCJLT), as it allows for efficient volume depletion, improves current ratios, enhances intrinsic gain, and enables enhancement-mode operation.
JOURNAL OF ELECTRONIC MATERIALS
(2023)
Proceedings Paper
Engineering, Multidisciplinary
Bikram Kishore Mahajan, Yen-Pu Chen, Ulisses Alberto Heredia Rivera, Rahim Rahimi, Muhammad Ashraful Alam
Summary: This paper focuses on the long-term integrated degradation of LDMOS transistors under radiation and proposes a universal degradation model. By conducting experiments and numerical simulations, a hot carrier degradation model is introduced to explore the physical origin of defects, and it is demonstrated that this model can be applied to other LDMOS devices as well.
2022 IEEE INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM (IRPS)
(2022)
Proceedings Paper
Engineering, Multidisciplinary
Bikram Kishore Mahajan, Yen-Pu Chen, Muhammad Ashraful Alam, Dhanoop Varghese, Srikanth Krishnan, Vijay Reddy
Summary: This paper investigates the issue of Hot Carrier Degradation (HCD) in LDMOS transistors, determining the physical mechanism through TCAD modeling. The capability of the Super Single Pulse Charge Pumping (SPCP-P-2) technique to extract N-IT(x) is demonstrated, and the spatial and temporal evolution of N-IT(x,t) is quantified and compared with TCAD predictions. Key differences between experimental and TCAD approaches are identified, and possible physical mechanisms are suggested.
2022 IEEE INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM (IRPS)
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Muhammad Ashraful Alam, Bikram Kishore Mahajan, Yen-Pu Cheri
Summary: This paper focuses on the implications of self-heating effect (SHE) on hot carrier degradation of CMOS and more-than-Moore devices, explaining how it affects different devices in different ways. The paper also discusses design strategies to reduce hot carrier degradation and suggests open problems for further research, paralleling discussions in reference [1] and serving as a companion article.
2021 5TH IEEE ELECTRON DEVICES TECHNOLOGY & MANUFACTURING CONFERENCE (EDTM)
(2021)
Proceedings Paper
Engineering, Multidisciplinary
Bikram Kishore Mahajan, Yen-Pu Chen, Dhanoop Varghese, Vijay Reddy, Srikanth Krishnan, Muhammad Ashraful Alam
Summary: This study identified multiple hotspots of HCD in LDMOS through experimentally validated TCAD simulations, introduced a novel charge pumping technique to probe region-specific interface states, and developed a unified multi-hotspot HCD model to interpret degradation kinetics in power transistors. The generalized charge pumping technique can be used to map interface states in various transistors with non-traditional doping and contact configurations.
2021 IEEE INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM (IRPS)
(2021)
Article
Engineering, Electrical & Electronic
Yen-Pu Chen, Bikram Kishore Mahajan, Dhanoop Varghese, Srikanth Krishnan, Vijay Reddy, Muhammad Ashraful Alam
Summary: This study introduces an enhanced version of the CP/SPCP techniques, named Super SPCP, to extract position-resolved localized degradations in SBT LDMOS, demonstrating its effectiveness in characterizing transistors with nontraditional doping profiles and contact configurations.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
