Article
Nanoscience & Nanotechnology
Xiao Long, Huan Tan, Saul Estandia, Jaume Gazquez, Florencio Sanchez, Ignasi Fina, Josep Fontcuberta
Summary: The electroresistance yield and endurance of ultrathin Hf0.5Zr0.5O2 (HZO) films can be improved by using a 1 nm SrTiO3 capping layer, reducing charge transport along grain boundaries. This strategy can be explored in polycrystalline films.
Article
Chemistry, Physical
Haiyan Chen, Lin Tang, Leyang Liu, Yonghong Chen, Hang Luo, Xi Yuan, Dou Zhang
Summary: This study demonstrates the improvement of ferroelectricity and reliability in 21.6 nm-thick Hf0.5Zr0.5O2 (HZO) films by inserting an ultrathin Al2O3 (AO) layer through interface modification. The electrostatic coupling between HZO and AO films contributes to enhanced ferroelectricity, while the AO layer acts as a dielectric capacitor to improve cycling reliability.
APPLIED SURFACE SCIENCE
(2021)
Article
Engineering, Electrical & Electronic
Jaidah Mohan, Yong Chan Jung, Heber Hernandez-Arriaga, Jin-Hyun Kim, Takashi Onaya, Akshay Sahota, Su Min Hwang, Dan N. Le, Jiyoung Kim, Si Joon Kim
Summary: This study investigates the correlation between imprint and polarization relaxation in ferroelectric HZO films, revealing the drastic relaxation effects due to imprint. Prepoled ferroelectric capacitors exhibit apparent imprint and strong polarization relaxation effects due to the development of built-in voltages.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Haiyan Chen, Hang Luo, Xi Yuan, Dou Zhang
Summary: This study demonstrates excellent ferroelectric properties in Hf0.5Zr0.5O2 (HZO) films by using an ultrathin Ti metal bottom electrode, and compares the effects of different top electrodes on capacitor performance. The research shows outstanding endurance and optimized interface quality in practical applications.
SCRIPTA MATERIALIA
(2022)
Article
Physics, Applied
Beom Yong Kim, Se Hyun Kim, Hyeon Woo Park, Yong Bin Lee, Suk Hyun Lee, Minsik Oh, Seung Kyu Ryoo, In Soo Lee, Seungyong Byun, Doosup Shim, Min Hyuk Park, Cheol Seong Hwang
Summary: The HfOxNy interfacial layer was found to decrease the relative proportion of the non-FE monoclinic phase, increase the double remanent polarization of the Hf0.5Zr0.5O2 thin film, and reduce fatigue degradation. The results demonstrate the importance of interfacial engineering for optimizing the FE properties.
APPLIED PHYSICS LETTERS
(2021)
Article
Multidisciplinary Sciences
Shu Shi, Haolong Xi, Tengfei Cao, Weinan Lin, Zhongran Liu, Jiangzhen Niu, Da Lan, Chenghang Zhou, Jing Cao, Hanxin Su, Tieyang Zhao, Ping Yang, Yao Zhu, Xiaobing Yan, Evgeny Y. Tsymbal, He Tian, Jingsheng Chen
Summary: The authors demonstrate the stabilization of the metastable orthorhombic phase in Hf0.5 Zr0.5O2 films through interface engineering and hole doping.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Applied
Peijie Jiao, Zhongnan Xi, Xiaoyu Zhang, Yajie Han, Yang Wu, Di Wu
Summary: Ferroelectric Hf0.5Zr0.5O2 films were deposited on Nb:SrTiO3 semiconductor substrates to form a Pt/Hf0.5Zr0.5O2/Nb:SrTiO3 metal/ferroelectric/semiconductor ferroelectric tunnel junction (FTJ). The FTJ exhibited a high tunneling electroresistance ratio, indicating potential for next-generation nonvolatile memories.
APPLIED PHYSICS LETTERS
(2021)
Article
Multidisciplinary Sciences
Sirui Zhang, Qinghua Zhang, Fanqi Meng, Ting Lin, Binjian Zeng, Lin Gu, Min Liao, Yichun Zhou
Summary: HfO2-based ferroelectrics with complementary metal-oxide semiconductor compatibility and robust ferroelectricity have attracted much attention. However, the unique wake-up effect of HfO2-based ferroelectric films hinders their performance improvement. This study investigates the domain structure of a Hf0.5Zr0.5O2 ferroelectric thin film and reveals the presence of 90 degrees and 180 degrees domains with different domain wall orientations. The findings provide fundamental information for understanding the domain structure of HfO2-based ferroelectrics.
Article
Chemistry, Multidisciplinary
Biyao Zhao, Yunting Yan, Jinshun Bi, Gaobo Xu, Yannan Xu, Xueqin Yang, Linjie Fan, Mengxin Liu
Summary: In this paper, the annealing effects of TiN/Hf0.5Zr0.5O2/TiN metal-ferroelectric-metal capacitors were investigated. It was found that microwave annealing significantly increased the twofold remanent polarization and inhibited the wake-up effect. The orthorhombic crystalline phase was observed with reduced interdiffusion in microwave annealing devices. Moreover, the microwave annealing treatment resulted in a lower leakage current and decreased defect density in the capacitors.
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
Chemistry, Multidisciplinary
Anastasia Chouprik, Vitalii Mikheev, Evgeny Korostylev, Maxim Kozodaev, Sergey Zarubin, Denis Vinnik, Svetlana Gudkova, Dmitrii Negrov
Summary: This study elucidates an approach to suppress the wake-up effect in ultrathin Hf0.5Zr0.5O2 films and reveals the important role of built-in fields in the ferroelectricity and stability of thin films.
Article
Physics, Applied
Zichong Zhang, Chengxu Wang, Yifan Yang, Xiangshui Miao, Xingsheng Wang
Summary: This paper discusses a mechanism and method for enhancing polarization in fabricated Hf0.5Zr0.5O2 (HZO) capacitors. The proposed reawakening voltage operation method (RVOM) increases the transient switching current and polarization in HZO films at elevated temperatures. The change in conduction mechanisms for the HZO capacitor current after RVOM can be observed by fitting leakage current curves. The generation of oxygen vacancies (V-O) by RVOM leads to an increase in leakage current and a degradation in the breakdown voltages of HZO capacitors, affecting their reliability.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Eduardo Barriuso, Panagiotis Koutsogiannis, David Serrate, Javier Herrero-Martin, Ricardo Jimenez, Cesar Magen, Miguel Alguero, Pedro A. Algarabel, Jose A. Pardo
Summary: This study presents the direct growth of single-phase epitaxial Hf0.5Zr0.5O2 films with non-centrosymmetric orthorhombic structure on electrode-free corundum substrates using pulsed laser deposition. The high-quality films belong to the Pca2(1) space group with [111] out-of-plane orientation. The surface of the films exhibits an atomic step-terrace structure with a corrugation of one atomic layer, and the films consist of grains with around 10 nm lateral size as observed by atomic force microscopy and scanning transmission electron microscopy. The polar nature of the films is confirmed by pyroelectric measurements, providing insights into the mechanisms of epitaxial stabilization of the ferroelectric phase of hafnia.
Article
Nanoscience & Nanotechnology
Ji Hye Lee, Hong Joon Kim, Eunjo Ryoo, Jinhyuk Jang, Sanghyeon Kim, Jeong Rae Kim, Se Young Park, Si-Young Choi, Tae Won Noh, Daesu Lee
Summary: The coexistence of multiple phases through thickness-driven phase transition in nanoscale CaTiO3 films can enhance the piezoelectric properties. This study highlights the potential of complex ferroelectrics for controlling the functionality of nanoscale electromechanical devices.
ADVANCED ELECTRONIC MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Michael Hoffmann, Mengcheng Gui, Stefan Slesazeck, Riccardo Fontanini, Mattia Segatto, David Esseni, Thomas Mikolajick
Summary: Utilizing ferroelectric negative capacitance in Hf0.5Zr0.5O2-based thin films shows great promise for nanoscale electronic devices. Investigating heterostructures reveals that the negative capacitance is intrinsic to the Hf0.5Zr0.5O2 layer, which is crucial for potential applications. Energy barrier for polarization switching in Hf0.5Zr0.5O2 is found to be independent of domain configuration and layer thickness, in agreement with first principles calculations.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Review
Chemistry, Multidisciplinary
Thomas Mikolajick, Min Hyuk Park, Laura Begon-Lours, Stefan Slesazeck
Summary: Due to the low voltage driven switching and nonvolatility, ferroelectric materials have great potential for low power nonvolatile electronic devices. However, the incompatibility of well-known ferroelectrics with existing semiconductor technology has hindered the competitiveness of these devices. The discovery of ferroelectricity in hafnium oxide has changed this situation. This article summarizes the material science of ferroelectricity in hafnium oxide, discusses the status of nonvolatile ferroelectric memories, explores applications like in-memory computing, and showcases the realization of neuromorphic computing systems using basic building blocks of spiking neural networks.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Azhar Fakharuddin, Konstantina-Kalliopi Armadorou, Leandros P. Zorba, Marinos Tountas, Tobias Seewald, Anastasia Soultati, Polychronis Tsipas, Emilia R. Schuetz, Nikolaos Tzoganakis, Stylianos Panagiotakis, Konstantina Yannakopoulou, Athanasios Dimoulas, Vassilis Psycharis, Emmanuel Kymakis, Abd Rashid bin Mohd Yusoff, Konstantinos Aidinis, Lukas Schmidt-Mende, Georgios C. Vougioukalakis, Mohammad Khaja Nazeeruddin, Maria Vasilopoulou
Summary: Inverted perovskite solar cells (PSCs) have gained attention due to their low-temperature fabrication process. However, the limited availability of electron transport materials, particularly the commonly used PCBM, compromises the efficiency and stability of the cells. In this study, a new electron transport material called EPF03 was synthesized and tested in inverted PSCs, showing a significant improvement in efficiency compared to PCBM. The results also suggest that EPF03 can enhance the stability and photostability of perovskite solar cells.
CHINESE JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Physical
Silvia Mauri, Gianluca D'Olimpio, Corneliu Ghica, Luca Braglia, Chia-Nung Kuo, Marian Cosmin Istrate, Chin Shan Lue, Luca Ottaviano, Tomasz Klimczuk, Danil W. Boukhvalov, Antonio Politano, Piero Torelli
Summary: This study investigates the surface reactivity of a Ni3Sn4 catalyst operating at 250 degrees C for hydrogen production from methanol decomposition. It is found that the catalytic reaction is driven by surface tin-oxide phases, which enhance catalyst durability and H2 selectivity. These findings provide new perspectives for the development of scalable and low-cost catalysts.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
E. Georgopoulou-Kotsaki, P. Pappas, A. Lintzeris, P. Tsipas, S. Fragkos, A. Markou, C. Felser, E. Longo, M. Fanciulli, R. Mantovan, F. Mahfouzi, N. Kioussis, A. Dimoulas
Summary: The 2D van der Waals ferromagnetic metals FexGeTe2 with x = 3-5 have attracted significant attention. In this study, epitaxial Fe5-dGeTe2 (FGT) heterostructures were grown on insulating crystalline substrates using Molecular Beam Epitaxy (MBE). The addition of Bi2Te3 topological insulator (TI) to FGT films significantly enhanced the saturation magnetization and Curie temperature (Tc), with record values of 570 K obtained.
Article
Physics, Applied
N. Figueiredo-Prestes, P. Tsipas, S. Krishnia, P. Pappas, J. Peiro, S. Fragkos, V. Zatko, A. Lintzeris, B. Dlubak, S. Chaitoglou, M. Heuken, N. Reyren, H. Jaffres, P. Seneor, A. Dimoulas, J. M. George
Summary: With the development of technologies utilizing quantum phenomena, research on alternative materials and heterostructure engineering has been opened up. This study focuses on the magnetotransport properties of TI/2D-FM heterostructures composed of Cr1+delta Te2/Bi2Te3 stacks grown by molecular-beam epitaxy. The results reveal high levels of effective torques, interfacial magnetoresistance effects, and anomalies in the anomalous Hall effect. The relevance of the TI/2D-FM interface and the preservation of polarized surface states are demonstrated.
PHYSICAL REVIEW APPLIED
(2023)
Article
Chemistry, Physical
Maria-Athina Apostolaki, Elias Sakellis, Polychronis Tsipas, Maria Giannouri, Spiros Gardelis, Nikos Boukos, Athanasios Dimoulas, Vlassis Likodimos
Summary: Heterostructured WO3/TiO2 photonic crystal films in the form of three-dimensional macroporous inverse opals were developed by single-step, three-phase co-assembly of colloidal templates with water soluble precursors. The properties of the inverse opals could be controlled by adjusting the W/Ti molar ratio and macropore diameter. This method provides a promising route for the development of heterostructured inverse opal networks with tailored electronic properties and improved solar light harvesting.
APPLIED SURFACE SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Ilaria Pallecchi, Federico Caglieris, Michele Ceccardi, Nicola Manca, Daniele Marre, Luca Repetto, Marine Schott, Daniel I. Bilc, Stefanos Chaitoglou, Athanasios Dimoulas, Matthieu J. Verstraete
Summary: The family of van der Waals dichalcogenides (vdWDs) includes a large number of compositions and phases, exhibiting varied properties and functionalities. They have opened up a novel electronics of two-dimensional materials, characterized by higher integration and interfaces which are atomically sharper and cleaner than conventional electronics. Among these functionalities, some vdWDs possess remarkable thermoelectric properties.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Chemistry, Physical
Stefanos Chaitoglou, Roger Amade, Rogelio Ospina, Enric Bertran-Serra
Summary: This study presents a bottom-up approach for depositing Mo carbide nanostructures on vertical graphene nanowall templates. The resulting compounds exhibit exceptional activities toward the hydrogen evolution reaction in acidic media. The high double-layer capacitance and low charge transfer resistance of these Mo2C on GNW hybrid compounds are the main causes of the enhanced HER activity. This study is expected to pave the way for the design of hybrid nanostructures based on nanocatalyst deposition on three-dimensional graphene templates.
ACS APPLIED ENERGY MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Martha Pylarinou, Elias Sakellis, Polychronis Tsipas, George Em. Romanos, Spiros Gardelis, Athanasios Dimoulas, Vlassis Likodimos
Summary: Homojunction engineering between Mo- and Ca-doped BiVO4 nanocrystals in the skeleton of photonic band gap engineered inverse opals is introduced as a strategy to improve the efficiency of nanostructured metal oxide photocatalysts. The nanostructured homojunction Mo-BiVO4/Ca-BiVO4 photonic films outperformed their individual constituents in photocurrent generation and photocatalytic degradation rate under visible light, showing great potential for water remediation by pharmaceutical micropollutants.
ACS APPLIED NANO MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Eleftherios Christopoulos, Mohamed M. Elsenety, Andreas Kaltzoglou, Constantinos C. Stoumpos, Mattia Gaboardi, Jasper R. Plaisier, Polychronis Tsipas, Elias Stathatos, Evangelos G. Vitoratos, Athanasios Dimoulas, Polycarpos Falaras
Summary: This study explores the use of the ionic liquid 1-hexyl-3-methylimidazolium iodide (HMImI) for the synthesis of a lead halide derivative, (HMIm)PbI3, which enhances the efficiency and stability of perovskite solar cells. The (HMIm)PbI3 compound forms 1D chains and acts as a semiconductor with a band gap of 2.85 eV. When deposited on top of the main perovskite absorber, it improves the radiative recombination and open circuit voltage by reducing trap state density, while preventing humidity penetration and ion migration.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Mattia Halter, Laura Begon-Lours, Marilyne Sousa, Youri Popoff, Ute Drechsler, Valeria Bragaglia, Bert Jan Offrein
Summary: Brain-inspired computing is a promising technology for handling the increasing amount of data in a connected society. This study presents the development of sub-μm-sized artificial synaptic weights using a ferroelectric field effect transistor. The device demonstrates a quasi-continuous resistance tuning of the synapse and fine-grained weight update, making it suitable for neuromorphic and cognitive computing.
COMMUNICATIONS MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Emanuele Longo, Lorenzo Locatelli, Polychronis Tsipas, Akylas Lintzeris, Athanasios Dimoulas, Marco Fanciulli, Massimo Longo, Roberto Mantovan
Summary: Properly tuning the Fermi level position in topological insulators is crucial for tailoring their spin-polarized electronic transport and improving device efficiency. In this study, a highly crystalline Bi2Te3/Sb2Te3 heterostructure was successfully grown on large area Si(111) substrates using in situ metal organic chemical vapor deposition. The surface Fermi level of Bi2Te3 was effectively tuned by growing it on top of Sb2Te3. A spin-charge converter based on this heterostructure was fabricated and its performance was verified through spin pumping ferromagnetic resonance. The results demonstrate the successful tuning of the surface Fermi level and have potential implications for future technology transfer.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Emigdio Chavez-Angel, Polychronis Tsipas, Peng Xiao, Mohammad Taghi Ahmadi, Abdalghani H. S. Daaoub, Hatef Sadeghi, Clivia M. Sotomayor M. Torres, Athanasios Dimoulas, Alexandros El Sachat
Summary: Using van der Waals epitaxy, we engineered highly insulating thermal metamaterials based on atomically thin lattice-mismatched Bi2Se3/MoSe2 superlattices and graphene/PdSe2 heterostructures, offering exceptional thermal resistances and ultralow cross-plane thermal conductivities comparable to those of amorphous materials. Experimental data supported by calculations reveal the impact of lattice mismatch, phonon-interface scattering, size effects, temperature, and interface thermal resistance on cross-plane heat dissipation, providing valuable insights into thermal transport characteristics and synthetic methods for large-area van der Waals films.
Article
Chemistry, Physical
Stefanos Chaitoglou, Rogelio Ospina, Yang Ma, Roger Amade, Xavier Vendrell, Jhonatan Rodriguez-Pereira, Enric Bertran-Serra
Summary: To accelerate the transition to a green economy based on hydrogen, this study introduces a bottom-up approach involving the carburization of Mo nanostructures on vertical graphene nanowalls supports. The resulting hybrid electrocatalysts show excellent efficiency and stability for hydrogen evolution reaction in acid electrolyte. This research paves the way for the design of hybrid nanostructures and holds great potential for driving the development of sustainable and efficient hydrogen production systems.
JOURNAL OF ALLOYS AND COMPOUNDS
(2024)
