Article
Materials Science, Multidisciplinary
Wenyue Zhao, Ze Li, Zhao Wang, Yazhou Peng, Lei Shi, Wenjing Hua, Jie Wang, Lidong Wang, Wei-Dong Fei, Yu Zhao
Summary: In this study, large and regulable electrocaloric effects at room temperature are achieved in PbZrO3/Ca3Mn2O7 bilayer films based on PbZrO3 phase transition, and the sign of adiabatic temperature change, ΔT, is determined by Ca3Mn2O7 thickness. The formed PbZrO3-Ca3Mn2O7 heterojunction reduces the carrier concentration of the film and establishes a built-in electric field, greatly enhancing the withstanding voltage of the bilayer films. A maximum positive ΔT of 66.5 K is obtained in the bilayer film with a thin Ca3Mn2O7 layer, while a negative ΔT of -9.9 K is obtained with a thick Ca3Mn2O7 layer, both near room temperature. This work presents a simple and effective approach to designing huge electrocaloric effects based on antiferroelectric-containing multilayers near room temperature.
Article
Multidisciplinary Sciences
Sangita Dutta, Pratyush Buragohain, Sebastjan Glinsek, Claudia Richter, Hugo Aramberri, Haidong Lu, Uwe Schroeder, Emmanuel Defay, Alexei Gruverman, Jorge Iniguez
Summary: Hafnia is a promising ferroelectric material in electronics due to its peculiar piezoresponse, which can be reversed by biaxial strain. The study demonstrates how controlling the environment of active oxygen atoms can change the sign of the piezoelectric response of the material.
NATURE COMMUNICATIONS
(2021)
Article
Engineering, Electrical & Electronic
Sanghyun Jo, Hyangsook Lee, Duk-Hyun Choe, Jung-Hwa Kim, Yun Seong Lee, Owoong Kwon, Seunggeol Nam, Yoonsang Park, Kihong Kim, Byeong Gyu Chae, Sangwook Kim, Seunghun Kang, Taehwan Moon, Hagyoul Bae, Jung Yeon Won, Dong-Jin Yun, Myoungho Jeong, Hyun Hwi Lee, Yeonchoo Cho, Kwang-Hee Lee, Hyun Jae Lee, Sangjun Lee, Kab-Jin Nam, Dongjin Jung, Bong Jin Kuh, Daewon Ha, Yongsung Kim, Seongjun Park, Yunseok Kim, Eunha Lee, Jinseong Heo
Summary: Ferroelectric zirconium-doped hafnia (Hf0.5Zr0.5O2) can be used to create negative differential capacitance behavior in capacitors and transistor gate stacks, providing reliable enhancements in switching performance. The effect is achieved in metal-oxide-semiconductor capacitors and field-effect transistors, leading to improved device performance with increased on current and decreased off current.
NATURE ELECTRONICS
(2023)
Article
Multidisciplinary Sciences
Kelli Ann Lynch, Tepie Meng, I Ponomareva
Summary: A computational methodology is proposed to simulate time dependent temperature variations using a thermostat approach. It is applied to study pyroelectricity under nonequilibrium conditions in ferroelectric PbTiO3. The nonequilibrium effects in pyroelectricity are found to manifest above 1.0 THz at room temperature, originating from the overlap with the intrinsic soft mode frequency. The proposed methodology can be used to predict equilibrium pyroelectric response by choosing a frequency of temperature variation below the intrinsic polar mode frequencies. The dynamics of ferroelectric phase transition can be probed with this methodology, revealing that it takes about a nanosecond for the computational supercell to undergo phase transition. Computational techniques capable of simulating picoseconds can compute pyroelectric response from nonequilibrium dynamical approach, while those that can reach nanoseconds are suitable for simulating phase transitions in ferroelectrics.
ADVANCED THEORY AND SIMULATIONS
(2022)
Article
Physics, Applied
A. P. Moina
Summary: Using a previously developed model, the study explores the electrocaloric effect (ECE) in antiferroelectric crystals of squaric acid, which undergoes a two-stage process with an intermediate ferrielectric phase during low-temperature polarization reorientation induced by an external electric field. The T-E landscape of the model entropy is analyzed. The ECE is found to be negative in the antiferroelectric phase, positive at low fields in the ferrielectric phase, and positive at all temperatures and fields in the ferroelectric phase. A negative EC temperature shift ΔT of approximately -2.7 K at 200 kV/cm is predicted. The supercritical behavior of the Gruneisen parameter in the crossover region between two bicritical end points is also studied.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Namik Kemal Gozuacik, Mustafa Cagri Bayir, M. Baris Okatan, I. Burc Misirlioglu, Sedat Alkoy, Ebru Mensur-Alkoy
Summary: This study investigates the effects of La substitution on the temperature dependent properties of PZT 70/30 ceramics and the electrocaloric effect induced by an external electric field. Experimental data and simulation results suggest that the gradual slanting of hystereses and reduction of transition temperature in La-doped samples are caused by the formation of dipolar defect complexes. The findings provide insights into the mechanism of electrocaloric effect and its potential applications in La-doped PZT 70/30 system.
Article
Chemistry, Multidisciplinary
Tian Gan, Zhe-Kun Xu, Jia-Qi Gan, Zhong-Xia Wang
Summary: Fluorine substitution is an effective method to construct high-performance molecular phase transition materials, enabling structural dimension engineering and high-temperature phase transition properties. In this study, (R-3-FPD)PbBr3 and (3,3-DFPD)(2)PbBr4 were successfully synthesized by fluorine substitution, exhibiting different crystal structures and phase transition characteristics.
Article
Chemistry, Multidisciplinary
Ruowei Yin, Junjie Li, Xiaopo Su, Shiqiang Qin, Chengye Yu, Yuxuan Hou, Chuanbao Liu, Yanjing Su, Lijie Qiao, Turab Lookman, Yang Bai
Summary: A multilayer ferroelectric structure with interlayer synergistic phase transitions is proposed to enhance the electrocaloric effect in ferroelectric materials, resulting in improved cooling performance for practical refrigeration applications.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Chemistry, Physical
V. S. Bondarev, E. A. Mikhaleva, M. V. Gorev, I. N. Flerov
Summary: The study found that the sensitivity of phase transition temperature to electric field in (NH4)(2)SO4 is very low, leading to a low maximum value of electrocaloric effect. However, the extensive electrocaloric response was relatively large, as shown by the analysis of the entropy-temperature-electric field phase diagram.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Multidisciplinary
Xiaolin Huang, Peng Tan, Yu Wang, Yao Zhang, Xing Wen, Guanchao Wang, Zhongxiang Zhou, Hao Tian
Summary: This study provides an effective approach to improving the EC performance of ferroelectrics with pronounced anisotropy by investigating the impact of anisotropic domain responses on the electrocaloric effect.
CRYSTAL GROWTH & DESIGN
(2022)
Article
Chemistry, Physical
C. M. Gonzalez-Henriquez, R. O. Vergara-Toloza, Patricio Romero-Hasler, E. A. Soto-Bustamante, W. Haase
Summary: The study focused on a polar system composed of a polymer and its monomer, where introducing saturated monomers led to different polar behaviors in the composite materials. Experimental results showed that composite materials with saturated monomers exhibited distinct electrical response characteristics compared to conventional counterparts.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Physics, Applied
Thorsten Schneider, Juliette Cardoletti, Hui Ding, Mao-Hua Zhang, Tianshu Jiang, Marton Major, Philipp Komissinskiy, Leopoldo Molina-Luna, Lambert Alff
Summary: An antipolar phase and thickness-dependent properties were confirmed for NaNbO3 thin films grown on SrTiO3 (100) substrates by pulsed laser deposition. Characteristic 1/4 superlattice reflections revealed the antipolar displacement of Na and Nb ions. X-ray diffraction showed two different orientations of the same phase for films beyond a critical thickness, with an explanation based on extraordinary strain compensation mechanism. The polarization vs electric field behavior exhibited a thickness dependence, with a stabilized antiferroelectric phase for very thin films and field induced ferroelectric hysteresis for thicker films.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Inorganic & Nuclear
Jun-Chao Liu, Fang-Fang Di, Yi-Piao Zeng, Wu-Jia Chen, Xiao-Yun Huang, Yan-Ling Luo, Xuan Zhu, Lin Zhou, Yuan-Yuan Tang
Summary: In this study, an above-room-temperature host-guest inclusion ferroelastic crystal was successfully designed and the phase transition temperature and type were effectively controlled by replacing the anion. The ferroelastic domains of this crystal can be switched under thermal stimulus as well as rapidly switched in situ under external stress, suggesting its potential in dual-channel switches.
INORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Physical
Hanen Abdmouleh, Issa Kriaa, Najmeddine Abdelmoula, Zina Sassi, Hamadi Khemakhem
Summary: Lead-free ceramic samples were successfully prepared using a solid-state reaction method, with identified morphotropic phase boundary and confirmed ferroelectric properties, dielectric constant behavior, and energy storage density. Additionally, an electrocaloric effect was determined for a specific sample near room temperature.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Multidisciplinary
Junjie Li, Hong-Hui Wu, Jianting Li, Xiaopo Su, Ruowei Yin, Shiqiang Qin, Dong Guo, Yanjing Su, Lijie Qiao, Turab Lookman, Yang Bai
Summary: The study presents a complex perovskite antiferroelectric material, PbMg0.5W0.5O3, with giant positive and negative electrocaloric effects near room temperature, suitable for refrigeration applications. This material exhibits large enthalpy change and symmetric peaks of ΔT at 36 degrees Celsius, showing potential for improved cooling efficiency and practical applications.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Review
Chemistry, Multidisciplinary
Ju Yong Park, Duk-Hyun Choe, Dong Hyun Lee, Geun Taek Yu, Kun Yang, Se Hyun Kim, Geun Hyeong Park, Seung-Geol Nam, Hyun Jae Lee, Sanghyun Jo, Bong Jin Kuh, Daewon Ha, Yongsung Kim, Jinseong Heo, Min Hyuk Park
Summary: The research on ferroelectric memories has been limited in the past due to scalability and compatibility issues. However, the discovery of ferroelectricity in certain oxides has revived interest in the field. The potential of inducing nanoscale nonvolatility in gate insulators has been demonstrated. However, technical limitations and variations in reliability need to be addressed for practical applications in various types of devices.
ADVANCED MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
H. Alex Hsain, Younghwan Lee, Suzanne Lancaster, Patrick D. Lomenzo, Bohan Xu, Thomas Mikolajick, Uwe Schroeder, Gregory N. Parsons, Jacob L. Jones
Summary: By inserting a 1 nm Al2O3 layer at the HZO/TiN interface, a protective passivating layer is introduced, resulting in improved remanent polarization and endurance of TiN/HZO/TiN capacitors.
Article
Chemistry, Multidisciplinary
Furqan Mehmood, Ruben Alcala, Pramoda Vishnumurthy, Bohan Xu, Ridham Sachdeva, Thomas Mikolajick, Uwe Schroeder
Summary: Further optimization of a Hf0.5Zr0.5O2 ferroelectric capacitor with TiN electrodes is achieved by introducing a non-ferroelectric La2O3 interfacial layer. The role of this interface in the reliability of the device for non-volatile memory applications is discussed, highlighting the importance of modifying the bottom interface for improved performance.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Ingmar Ratschinski, Soundarya Nagarajan, Jens Trommer, Andrei Luferau, Muhammad Bilal Khan, Artur Erbe, Yordan M. Georgiev, Thomas Mikolajick, Sean C. Smith, Dirk Koenig, Daniel Hiller
Summary: Silicon nanowires (Si NWs) in the form of nanosheets are used as building blocks for future transistors. However, doping Si NWs with few nanometers in diameter faces challenges. A novel doping concept inspired by III-V semiconductors is proposed, where Al-doped SiO2 shells are used as modulation doping material. Experimental results show a significant reduction in electrical resistance of Si NWs with Al-doped SiO2 shells compared to undoped SiO2 shells, supporting the effectiveness of surface functionalization for modulation doping.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Giulio Galderisi, Christoph Beyer, Thomas Mikolajick, Jens Trommer
Summary: Three-gated reconfigurable field-effect transistors have attracted significant interest in various fields due to their capability of n/p-type reconfiguration. Therefore, it is important to understand the temperature ranges in which these devices can operate and the underlying physical mechanisms. In this study, we conducted extensive observations on the operation of these devices in an ultrawide temperature range (80-475 K) and presented the results for their ambipolar and low VT operation modes. The data provided valuable insights into the temperature-dependent physical mechanisms governing the functionality of three-gated reconfigurable field-effect transistors.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Engineering, Electrical & Electronic
Bohan Xu, Liam Collins, Kristina M. Holsgrove, Thomas Mikolajick, Uwe Schroeder, Patrick D. Lomenzo
Summary: Over a decade ago, ferroelectricity was discovered in doped HfO2 thin films. In this work, undoped ZrO2 thin films were synthesized with different ozone dose times, and their ferroelectric and pyroelectric properties were studied. The results showed that the in-plane tensile stress and oxygen vacancy content significantly influenced the ferroelectric and pyroelectric behavior in the ZrO2 thin films. The low thermal budget for processing these films is valuable for semiconductor back-end-of-line processes.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Roberto Guido, Thomas Mikolajick, Uwe Schroeder, Patrick D. Lomenzo
Summary: Aluminum scandium nitride (Al1-x Sc x N) with large remanent polarization is attractive for high-density ferroelectric random-access memories. However, its cycling endurance is lower than other ferroelectric materials. Understanding the breakdown mechanism is crucial for improving memory reliability. Filaments formed due to impulse thermal process along defective pathways are proposed to play a role in the breakdown of Al1-x Sc x N ferroelectric capacitors. Stable bipolar filamentary resistive switching has been reported for the first time.
Article
Engineering, Electrical & Electronic
Moritz Engl, Thomas Mikolajick, Stefan Slesazeck
Summary: This paper presents a measurement procedure to characterize the degradation of hysteresis free charge amplification in unipolar operation of negative capacitance capacitors. Two different degradation processes are identified, which are related to remanent switching of domains and a change in the electrical internal bias field.
SOLID-STATE ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Soundarya Nagarajan, Thomas Mikolajick, Jens Trommer
Summary: This study investigates the impact of boron dopant segregation on carrier density in silicon nanowires and ohmic contact formation. The results indicate that oxidation at high temperatures reduces the active carrier density, while dopant surface segregation during thermal formation enables low-resistance ohmic contacts.
SOLID-STATE ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Geun Hyeong Park, Dong Hyun Lee, Hyojun Choi, Taegyu Kwon, Yong Hyeon Cho, Se Hyun Kim, Min Hyuk Park
Summary: This paper comprehensively reviews the emerging antiferroelectricity of fluorite-structured oxides and discusses their potential applications in semiconductor devices.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Jun Okuno, Tsubasa Yonai, Takafumi Kunihiro, Yusuke Shuto, Ruben Alcala, Maximilian Lederer, Konrad Seidel, Thomas Mikolajick, Uwe Schroeder, Masanori Tsukamoto, Taku Umebayashi
Summary: In this study, we investigated fatigue and recovery phenomenon of hafnium-based one-transistor and one-capacitor (1T1C) ferroelectric random-access memory (FeRAM) using PVD-TiN (30 nm)/ALD- Hf0.5Zr0.5O2 (8 nm)/CVD-TiN (50 nm) capacitors. A single large capacitor was fabricated to understand the recovery mechanism and evaluate the recovery effect. The results revealed that the recovery effect is caused by domain depinning and new domains switching due to oxygen vacancy redistribution. It was also found that the recovery voltage can be reduced by applying a longer recovery pulse width, allowing for more flexible circuit design of 1T1C FeRAM when the recovery method is utilized to enhance cycling endurance.
IEEE JOURNAL OF THE ELECTRON DEVICES SOCIETY
(2023)
Correction
Chemistry, Multidisciplinary
Se Hyun Kim, Geun Taek Yu, Geun Hyeong Park, Dong Hyun Lee, Ju Yong Park, Kun Yang, Eun Been Lee, Je In Lee, Min Hyuk Park
CHEMICAL COMMUNICATIONS
(2023)
Review
Nanoscience & Nanotechnology
Jaewook Lee, Kun Yang, Ju Young Kwon, Ji Eun Kim, Dong In Han, Dong Hyun Lee, Jung Ho Yoon, Min Hyuk Park
Summary: HfO2 is a promising material for emerging ferroelectric and resistive switching memory devices due to its excellent electrical properties and compatibility with existing fabrication processes. The presence of oxygen vacancies (Vo) in HfO2 films greatly affects the material properties, device performance, and reliability. Understanding the formation mechanism and effects of Vo is crucial for improving the performance and reliability of HfO2-based devices.
Article
Engineering, Electrical & Electronic
Jianran Zhang, Carsten Strobel, Kathrin Estel, Thomas Mikolajick, Robert Kirchner
Summary: Direct writing laser lithography has gained popularity due to its mask-free nature. Among the various techniques, two-photon absorption direct laser writing can create smaller features. However, prolonged immersion can render the photoresist unresponsive, leading to the proposal of using a combination of different immersion liquids and air direct writing for optimal results.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(2023)
Article
Chemistry, Multidisciplinary
Luis Azevedo Antunes, Richard Ganser, Uwe Schroeder, Thomas Mikolajick, Alfred Kersch
Summary: The phase composition of HZO thin films is crucial for their ferroelectric and electrical properties, but optimizing the phase formation is a challenge due to the complex influencing variables. The Curie temperature is an important parameter that depends on Zr content, oxygen-related defects, layer thickness, and external stress. A two-step process of phase formation involving kinetic transformation and nucleation is proposed. A modified nucleation model with consideration of polycrystalline structure and rescaled interface energies is used to calculate phase fractions and analyze the causes of undesired monoclinic phase.
ADVANCED MATERIALS INTERFACES
(2023)
