Article
Engineering, Electrical & Electronic
Yongqi Ruan, Qi Zhang, Michael Lord, Yizhong Guo, Jinzhao Wang, Jiaolian Liu, Zhijun Ma, Peng Zhou, Tianjin Zhang, Nagarajan Valanoor
Summary: This study investigates the current-voltage (I-V) characteristics and ON/OFF ratio in hafnium oxide (HfO2)-based ferroelectric tunnel junctions (FTJs) under different poling sequences. The results show that the ON/OFF ratio doubles when a -5 V poling pulse is applied prior to a +5 V pulse. It is also found that the ON-state exhibits Ohmic behavior while the OFF-state shows nonlinearity, indicating direct tunneling across a barrier. The study explains the poling sequence-dependent tunneling electroresistance by the evolution of domain structure in the ferroelectric films.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
L. N. Jiang, Yun-Peng Wang, Y. Zhu, X. F. Han
Summary: The long electrical screening length of an insulator allows changes in local ferroelectric polarization to affect the electrostatic potential across the entire insulating region, enhancing the tunneling electroresistance effect. First-principles calculations of multiferroic tunnel junctions reveal a unique local ferroelectric polarization at the interface, leading to an optimistic TER ratio.
Article
Chemistry, Multidisciplinary
Natalia Andreeva, Anatoliy Petukhov, Oleg Vilkov, Adrian Petraru, Victor Luchinin
Summary: The study uses scanning tunneling spectroscopy in ultrahigh vacuum conditions and conductive atomic-force microscopy in ambient conditions to investigate the local electroresistive properties of ferroelectric tunnel junctions. The experimental current-voltage characteristics show dependence on the measurement technique applied, as the screening conditions of the polarization charges differ for the two scanning probe techniques. Additionally, the asymmetry of the tunnel barrier height for opposite ferroelectric polarization orientations may be influenced by the method used to study local tunnel electroresistance.
Article
Nanoscience & Nanotechnology
Yeong Jae Shin, Juan Jiang, Yichen Jia, Frederick J. Walker, Charles H. Ahn
Summary: BaTiO3 exhibits functional properties like high dielectric constant, large Pockels coefficient, and strong ferroelectricity/piezoelectricity, which can be used for various applications including non-volatile memory devices. Synthesis of BaTiO3 thin films by molecular beam epitaxy allows for growth of coherently strained and ferroelectric BaTiO3 at low temperatures, paving the way for large-scale integration with mainstream electronics platforms. Experimental results demonstrate surface mobility of BaO and TiO2 adatoms conducive to ferroelectric crystal growth at low temperatures.
Article
Materials Science, Multidisciplinary
Hui Gan, Shengchun Shen, Yaoxin Li, Yuewei Yin, Xiaoguang Li
Summary: We find that the electronic structures and transport properties of ferroelectric tunnel junctions (FTJs) are highly influenced by the types and locations of oxygen vacancies (OVs) in the ferroelectric barrier. The presence of OVs leads to the formation of local tail-to-tail domain walls, which alters the ferroelectricity of the barrier and the local density of states in the TiO2 layers. Consequently, the tunneling electroresistance (TER) effect is enhanced in the presence of OVs and is sensitive to their types and locations. These findings are crucial for the design of FTJs.
Article
Chemistry, Physical
Jin Yuan, Jian-Qing Dai, Miao-Wei Zhao
Summary: This study theoretically demonstrates that Pt/BiAlO3/Pt (Pt/BAO/Pt) structures can achieve a giant tunneling electroresistance (TER) effect, comparable to van der Waals tunnel junctions, by switching the electric polarization of the ferroelectric barrier. Furthermore, the use of a graphene monolayer can enhance the TER effect and improve the writing endurance of FTJ memories.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Shuli Yang, Lili Kang, Xiaohong Zheng, Peng Jiang, Gaofeng Zhao
Summary: In this study, a vertical 3D FTJ was designed by combining 2D ferroelectric material In2Se3 with 3D metal Au and using h-BN as a insulator. The introduction of h-BN intercalation broke the symmetry of the electrodes and resulted in a TER ratio of about 1200%.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Engineering, Electrical & Electronic
Pengying Chang, Yiyang Xie
Summary: In order to enhance the performance of HfO2-based ferroelectric (FE) tunnel junctions (FTJs) and their crossbar arrays, we propose using low-barrier Ta2O5 dielectric material to increase device asymmetry. By inserting Ta2O5 between two FE HfO2 barriers for resonant band engineering, both JON and TER ratio are significantly improved, while good retention is maintained due to the high permittivity of Ta2O5. Additionally, high current rectification ratio and negative differential resistance are observed. These abundant physical effects in HfO2/Ta2O5/HfO2 based MFIFM resonant FTJs may enable selector-less crossbar.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Lili Kang, Peng Jiang, Xiaoli Zhang, Hua Hao, Xiaohong Zheng, Lei Zhang, Zhi Zeng
Summary: This study explores the quantum transport properties of 2D FTJs by constructing two different types of FTJs with partial polarization reversal to form domain walls, achieving a high TER ratio through quantum transport calculations. Analysis of the electronic structure reveals charge accumulation or depletion at the domain walls, leading to a giant TER ratio.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2021)
Article
Nanoscience & Nanotechnology
Bhagwati Prasad, Vishal Thakare, Alan Kalitsov, Zimeng Zhang, Bruce Terris, Ramamoorthy Ramesh
Summary: Ferroelectric tunnel junctions (FTJs) based on Hafnia with Hf0.5Zr0.5O2 (HZO) barrier have shown great promise for non-volatile memory applications. By stabilizing the rhombohedral polar phase of HZO through a large compressive strain, robust ferroelectricity was achieved with approximately 1 nm thick films grown epitaxially on a SrTiO3 (001) substrate, leading to improved signal-to-noise ratio during read operations.
ADVANCED ELECTRONIC MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Dahye Kim, Jihyung Kim, Seokyeon Yun, Jungwoo Lee, Euncho Seo, Sungjun Kim
Summary: This paper proposes a ferroelectric tunnel junction using hafnium aluminum oxide as the ferroelectric layer, and demonstrates its capability as a synaptic device through electrical analysis and experiments. The maximum remanent polarization and threshold electric field values are evaluated for different device conditions. Furthermore, the study shows that the hafnium aluminum oxide-based junction can exhibit synaptic plasticity and be utilized for reservoir computing. The synaptic properties of the ferroelectric tunnel junction are verified for the feasibility of its implementation as an artificial synaptic device.
Article
Engineering, Electrical & Electronic
Hsin-Hui Huang, Yueh-Hua Chu, Tzu-Yun Wu, Ming-Hung Wu, I-Ting Wang, Tuo-Hung Hou
Summary: A comprehensive physical model is established to understand the device operation and optimization strategy of the ferroelectric tunnel junction. The model is capable of simulating various operations and has good agreement with experiments. The optimization strategy for the thickness of the ferroelectric layer and nonpolar interfacial layer is discussed, as well as the possible misinterpretation of measured results.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Chemistry, Physical
Minghao Liu, Ting Liao, Ziqi Sun, Yuantong Gu, Liangzhi Kou
Summary: Two-dimensional ferroelectric materials are considered promising for high-performance nanoelectronic devices due to their bistable and switchable polarization states which provide non-volatility, high storage density, low energy cost, and short response time. This mini review discusses the mechanism and operation principles of ferroelectric devices and summarizes the latest research progress on electronic devices based on 2D ferroelectrics, providing perspectives for future research and development directions in various fields. This overview aims to highlight the application of 2D ferroelectrics in electronic devices.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Qinqin Wang, Ti Xie, Nicholas A. Blumenschein, Zhihao Song, Aubrey T. Hanbicki, Michael A. Susner, Benjamin S. Conner, Tony Low, Jian-Ping Wang, Adam L. Friedman, Cheng Gong
Summary: This study demonstrates high-performance FTJs constructed with graphene and a two-dimensional ferroelectric material, showing high tunneling electroresistance and gate tunability. This structure has potential applications in energy-efficient non-volatile memories and computing.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Pengying Chang, Gang Du, Jinfeng Kang, Xiaoyan Liu
Summary: This study investigates the tunneling processes of ferroelectric tunnel junction (FTJ) based on metal-ferroelectric-insulator-semiconductor (MFIS) stack for both n-type and p-type semiconductor electrodes using an experimentally calibrated model. The research shows that the conduction modes of n-type and p-type MFIS can be classified depending on the contribution of minority carriers in the semiconductor, and the optimal tunneling electroresistance (TER) for each device is achieved under different operating conditions. The findings provide insights into the band structure engineering of the MFIS structure for designing and optimizing FTJ performance.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Materials Science, Ceramics
Zhihua Tian, Xueqin Xu, Jingwen Tang, Qianqian Zhang, Fushuo Wu, Peigen Zhang, Jian Liu, ZhengMing Sun
Summary: In this study, nano-sized carbides and metal whiskers were efficiently prepared by mechanochemical decomposition of MAX phases, providing a promising alternative route for large-scale synthesis. The method has potential applications in various high technology industries.
INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY
(2023)
Article
Chemistry, Physical
Yongda Chen, Ruxin Liu, Xu Zhang, Wenzhuo Zhuang, Chong Zhang, Wei Niu, Chunchen Zhang, Peng Wang, Wensheng Yan, Li Pi, Fengqi Song, Yunzhong Chen, Yongbing Xu, Rong Zhang, Xuefeng Wang
Summary: A new strategy to greatly enhance the spin polarization at the interfaces of LaAlO3/SrTiO3 by inserting a SrCoO2.5-patterned Hall-bar layer is demonstrated. The modified interface shows strong signatures of spin polarization and a significantly high transition temperature of 100 K.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Multidisciplinary
Han Xiao, Wenzhuo Zhuang, Leyi Loh, Tao Liang, Anabil Gayen, Peng Ye, Michel Bosman, Goki Eda, Xuefeng Wang, Mingsheng Xu
Summary: This work demonstrates the van der Waals epitaxial growth of air-stable 2D magnetic CrS2 on mica substrate by chemical vapor deposition (CVD). The CrS2 crystallites exhibit a metallic behavior with a moderate conductivity and room-temperature ferromagnetism. The results offer a new platform for further research and spintronic device applications.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Ruxin Liu, Liang Si, Wei Niu, Xu Zhang, Zhongqiang Chen, Changzheng Zhu, Wenzhuo Zhuang, Yongda Chen, Liqi Zhou, Chunchen Zhang, Peng Wang, Fengqi Song, Lin Tang, Yongbing Xu, Zhicheng Zhong, Rong Zhang, Xuefeng Wang
Summary: Through UV-light irradiation, a photocarrier-doping-induced Mott-insulator-to-metal phase transition is observed in a few atomic layers of perovskite intermediate-spin ferromagnetic SrRuO3-delta. This new metastable metallic phase can be reversibly regulated by the convenient photocharge transfer from SrTiO3 substrates to SrRuO3-delta ultrathin films.
ADVANCED MATERIALS
(2023)
Article
Materials Science, Ceramics
Hui Li, Shaohan Li, Litao Sun, Jing Zhang, Jin Yu, ZhengMing Sun, Weiwei Sun, Igor Di Marco
Summary: This study used density functional theory to explore the likelihood of exfoliating MXenes from 36 M(2)AC MAX phases and introduced two novel criteria to assess the probability of exfoliation. The results showed that these criteria are feasible, reliable, and easily accessible. Additionally, key features that are correlated with exfoliation were identified, providing deep insight into the synthesis process of MXenes and accelerating the discovery of new MXenes.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Zhe Ying, Bo Chen, Chunfeng Li, Boyuan Wei, Zheng Dai, Fengyi Guo, Dengfeng Pan, Haijun Zhang, Di Wu, Xuefeng Wang, Shuai Zhang, Fucong Fei, Fengqi Song
Summary: Building a van der Waals heterostructure can ignite interface magnetic ordering of magnetic topological insulators, which helps to reveal novel quantum states and design functional devices.
Article
Nanoscience & Nanotechnology
Wenxuan Sun, Yequan Chen, Wenzhuo Zhuang, Zhongqiang Chen, Anke Song, Ruxin Liu, Xuefeng Wang
Summary: We report the spin-to-charge conversion (SCC) in Mo0.25W0.75Te2-x (MWT)/Y3Fe5O12 (YIG) heterostructures at room temperature. The amorphous MWT films are deposited on liquid-phase-epitaxial YIG using pulsed laser deposition. The significant SCC voltage with a spin Hall angle of 0.021 is measured in the MWT layer by spin pumping experiments. Control experiments with MgO or Ag layers inserted between MWT and YIG confirm that the SCC is mainly attributed to the inverse spin Hall effect.
Article
Chemistry, Physical
Xueqin Xu, Dawei Sha, Zhihua Tian, Fushuo Wu, Wei Zheng, Li Yang, Shengyu Xie, Peigen Zhang, ZhengMing Sun
Summary: Ball milling is an effective method for preparing nano-sized Ti2InC, which exhibits high capacity and cycling stability as a lithium storage anode. The exfoliation of indium atoms by ball milling contributes to the capacity enhancement. In situ XRD analysis reveals that the capacity of nano-sized Ti2InC mainly comes from the lithiation of exfoliated indium atoms, and the ball-milled indium atoms can increase the initial capacity. The cycling process can activate and exfoliate Ti2InC grains, leading to an increased capacity.
NANOSCALE HORIZONS
(2023)
Article
Chemistry, Physical
Dawei Sha, Yurong You, Rongxiang Hu, Xin Cao, Yicheng Wei, Heng Zhang, Long Pan, ZhengMing Sun
Summary: Se anions are purposefully doped into a model conversion-type In2S3@C anode material to enhance the rate capability and cyclability of potassium-ion batteries. The Se doping regulates the electronic structure and weakens the bonding strength of In2S3-xSex, resulting in fast K+ intercalation and high conversion reactivity. This work provides a new guideline for designing advanced anion-doping conversion-type anode materials of potassium-ion batteries.
ENERGY STORAGE MATERIALS
(2023)
Review
Energy & Fuels
Xuesi Wang, Qiushi Ruan, Zhengming Sun
Summary: This review provides a comprehensive overview of the reaction mechanism of alkaline hydrogen evolution reaction (HER), focusing on the influence of electrocatalytic local environment on reaction kinetics. The authors discuss the methodology for studying and altering the electrocatalytic interface via in situ approaches. The aim is to offer new strategies and guidelines for studying and engineering the electrocatalytic local environment in alkaline HER.
Article
Chemistry, Physical
Jingyuan Qiao, Dingding Dong, Quanying Lin, Lingqiao Kong, Wenjie Jiang, Wei He, Zhengming Sun
Summary: In this study, a Zr and Ir codoped SrCo0.8Fe0.2O3-delta nanosheet with a two-dimensional porous structure was prepared using a self-template strategy. The porous configuration enhanced the accessible surface area of the ions, and the Zr and Ir substitution significantly improved the intrinsic activity of the sample. As a result, the SCFZI porous nanosheet exhibited low overpotential and high stability in 0.1 M KOH, providing an approach for developing perovskite catalysts with high activity and stability.
ACS APPLIED ENERGY MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Xiaodan Yin, Wei Zheng, Haifeng Tang, Peigen Zhang, ZhengMing Sun
Summary: In this study, 1T-MoS2/Ti3C2Tz 2D/2D heterostructures were synthesized as new electrode materials through a simple hydrothermal method. The existence of heterojunctions was confirmed by XPS and TEM analysis. The heterostructures exhibited superior electrochemical performance in a water-in-salt electrolyte, with an optimized ratio of 1T-MoS2/Ti3C2Tz at 2:1, achieving a specific capacitance of 250 F g(-1), a capacitance retention of 82.3% after 5000 cycles, and an average coulombic efficiency of 99.96%. Assembled into symmetric supercapacitors, it achieved an energy density of 12.0 W h kg(-1) at a power density of 139.9 W kg(-1), with a capacitance retention of 82.6% and an average coulombic efficiency of 99.95% after 5000 cycles at 5 A g(-1). This research is expected to stimulate further studies on the wide application of 2D/2D heterostructures in supercapacitors.
Article
Chemistry, Physical
Yajun Zhang, Rongxiang Hu, Peigen Zhang, Long Pan, ZhengMing Sun
Summary: Gradient structure design is crucial for strong and broadband microwave absorption. However, existing gradient structures are not suitable for mass production due to their multilayered fabrication process. In this study, a novel single-layer gradient structure (SLGS) was developed using gravity-induced sedimentation of Ni@Ti3C2Tx in a PVA matrix. The SLGS demonstrated impressive absorbing performance with a minimum reflection loss of -57.7 dB and an effective absorbing bandwidth of 3.2 GHz. The success of this work lies in the remarkable impedance matching and the ability to tune microwave absorbing performance through filler distribution in the matrix.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Chemistry, Multidisciplinary
Fushuo Wu, Zhihua Tian, Peiying Hu, Jingwen Tang, Xueqin Xu, Long Pan, Jian Liu, Peigen Zhang, ZhengMing Sun
Summary: This study successfully prepared polyacrylonitrile (PAN) nanofiber films with excellent electromagnetic interference (EMI) shielding and Joule heating performances. By coating the films with polypyrrole (PPy) and MXene nanosheets, the EMI shielding effectiveness and Joule heating ability of the films were significantly enhanced, showing potential applications in smart and wearable devices.
Article
Chemistry, Multidisciplinary
Hanning Zhang, Pengyu Chen, Huan Xia, Gang Xu, Yaping Wang, Tengfei Zhang, Wenwen Sun, Muhammadali Turgunov, Wei Zhang, ZhengMing Sun
Summary: Alloy-based anodes have high theoretical capacity but suffer from volume expansion and irreversible pulverization. This study combines liquid metal and MXene materials to achieve self-healing during lithium ion extraction and to buffer volume expansion. The resulting alloy anode shows excellent rate capability and cycling stability.
ENERGY & ENVIRONMENTAL SCIENCE
(2022)
