Article
Materials Science, Multidisciplinary
Suresh Addepalli, S. V. Jagadeesh Chandra, E. V. Krishna Rao, Uthanna Suda
Summary: Metal-insulator-metal (MIM) devices with Al/Al2TiO5 stack were fabricated and the effect of synthesized oxygen flow rate on their properties was studied. The results showed that the Al2TiO5 films exhibited good electrical properties, with high dielectric constant and low leakage current density.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2023)
Article
Chemistry, Physical
Yuan Guo, Shixin Wang, Xianfeng Du, Shuaizhong Liang, Shan Huang, Shengjun Peng, Yuehong Xie, Mingbo Ma, Lilong Xiong
Summary: Energy storage technology is crucial for a clean and sustainable energy supply. This study demonstrates a promising strategy for developing new energy storage devices with high energy and power density by using laser etching to obtain spatial multilayer VCNTs electrode nano-templates. The MIM capacitors constructed in this way have high planar capacity density, low leakage characteristic, and excellent performance stability.
ENERGY STORAGE MATERIALS
(2023)
Article
Environmental Sciences
Lifeng Chen, Zihao Jiao, Xiangbiao Yin, Wenlong Li, Xinpeng Wang, Shunyan Ning, Yuezhou Wei
Summary: This study synthesized a porous zirconium phosphate adsorbent using a sol-gel process and evaluated its performance in removing radioactive Sr2+ in wastewater. The experimental results demonstrated that the adsorbent exhibited excellent selectivity and high adsorption capacity, indicating its promising application prospects.
JOURNAL OF ENVIRONMENTAL MANAGEMENT
(2022)
Article
Engineering, Electrical & Electronic
Eduardo Moctezuma-Pascual, Reydezel Torres-Torres
Summary: This study presents a parameter extraction methodology for the microwave behavior of MIM capacitors, experimentally validated up to 60 GHz with different total effective areas, and successfully determines the permittivity of the thin film dielectric by applying the model after removing the effects introduced by the test fixture.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Engineering, Electrical & Electronic
Chunling Chen
Summary: An ultraminiature circularly polarized microstrip patch antenna is designed using four metal-insulator-metal (MIM) capacitors. Lumped capacitors are added to the edge of the conventional microstrip patch antenna for simulation of the theoretical model. It is found that careful selection of capacitors enables the microstrip patch antenna to achieve electrically small (ka < 1). The capacitors optimize axial ratio and resonance, providing an effective method for designing a compact circularly polarized antenna. The proposed method is validated through the design, fabrication, and measurement of a circularly polarized electrically small microstrip patch antenna.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2023)
Article
Biochemistry & Molecular Biology
Li Xiong, Jin Hu, Zhao Yang, Xianglin Li, Hang Zhang, Guanhua Zhang
Summary: This study presents the construction and dielectric properties investigation of metal-insulator-metal capacitors based on atomic-layer-deposition Al2O3/TiO2/HfO2 dielectric films. The influence of dielectric layer material and thickness on the performance of the capacitors was systematically investigated. Among them, the 25 nm Al2O3-based dielectric capacitor exhibited superior electrical performance and stability.
Review
Energy & Fuels
Muhammad Zahir Iqbal, Umer Aziz
Summary: Supercapattery devices have attracted attention for their high specific energy without compromising specific power, and utilizes advanced materials for improved performance. However, challenges remain in increasing energy density without affecting power density.
JOURNAL OF ENERGY STORAGE
(2022)
Article
Crystallography
Janusz Partyka, Katarzyna Pasiut, Dawid Kozien
Summary: The experiment aimed to determine the effect of strontium oxide on the recrystallization of zirconium silicate in glaze composition. The addition of strontium oxide affected the firing temperatures and microstructure of the glazes, resulting in an increase in the homogeneity of zirconium silicate distribution.
Article
Engineering, Electrical & Electronic
Marcello Ravasio
Summary: This paper presents an innovative process flow for building a MIM capacitor, which saves process steps and meets all morphological requirements. The flow involves depositing a sacrificial layer during top electrode patterning in a dry etching tool to form disposable spacers, reducing the risk of electrical leakage. The film deposition and control process and benefits of the suggested sequence are also discussed.
MICROELECTRONIC ENGINEERING
(2021)
Article
Materials Science, Ceramics
Yue Zhou, William G. Fahrenholtz, Joseph Graham, Gregory E. Hilmas
Summary: This study investigates the lattice thermal conductivities and thermodynamic properties of Zr2C and Zr2CO through first-principles calculations. The results show that filling oxygen in the lattice enhances the mechanical properties of Zr2C and reduces its lattice thermal conductivity, while Zr2CO exhibits higher heat capacity and thermal expansion coefficient.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2022)
Article
Materials Science, Ceramics
Yue Zhou, William G. Fahrenholtz, Joseph Graham, Gregory E. Hilmas
Summary: The theoretical study analyzed the lattice thermal conductivity variations of ZrC with different Hf contents, revealing that the addition of Hf resulted in decreased lattice thermal conductivity by reducing the phonon frequency. The electronic structure of ZrC was not significantly altered by the Hf additions.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2021)
Article
Materials Science, Ceramics
Dong-Run Hu, Naoyoshi Nunotani, Nobuhito Imanaka
Summary: Novel ZrSn1-xCoxO4-delta catalysts were synthesized for the direct decomposition of N2O. The doping of Co2+/3+ into the ZrSnO4 lattice improved the catalyst activity and durability. Among the catalysts, Zr1.17Sn0.73Co0.10O4-delta exhibited the highest activity decomposing N2O completely at 550 degrees C and showed high durability in the presence of CO2, O-2, and H2O vapor.
INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY
(2023)
Article
Physics, Applied
Hidenori Yamada, Toshishige Yamada
Summary: A model for ultracapacitor capacitance and ion screening length based on semiconductor physics is presented, showing the relationship between screening length and capacitance in a double-layer. Effective bandgap of the electrolyte/solvent pair is related to dissolved ion density, which in turn influences the capacitance and screening length dependence on temperature. The estimated effective bandgap for commonly used electrolytes in ultracapacitors is on the order of a few 100meV.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Liron Shvilberg, Takanori Mimura, Haotian Xue, Jonathan J. Wierer Jr, Elizabeth A. Paisley, Helge Heinrich, Jon F. Ihlefeld
Summary: A robust dielectric insulating layer for wide bandgap semiconductor devices is a challenge, and magnesium oxide shows promise as a suitable material for integration with gallium nitride (GaN). However, large area growth and smooth growth surfaces remain obstacles. This study presents the results of epitaxial growth of magnesium oxide on n-type GaN, showing low leakage currents and low interface state densities, indicating that the interfacial phase is not detrimental to the interfacial electronic properties of MOSCap devices.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Anis Allagui, Di Zhang, Ahmed Elwakil
Summary: This study provides experimental evidence supporting Westerlund's conjecture that Dead Matter Has Memory (Westerlund, 1991). Recent studies have observed and reported memory effects in the dynamic response of electric double-layer capacitors (EDLCs), which integrate their prior history of stimulation and state. Different excitation signals were used to quantify these effects, aiming to charge the same device to the same voltage and accumulated charge level but in different ways. It was observed that different yet repeatable discharge patterns occur, proving the existence of memory. This brief aims to provide further experimental evidence of the inherent memory effect in EDLCs in response to time-varying stationary input excitations with different statistical properties.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS
(2023)
Article
Chemistry, Physical
Ludovic Goffart, Bernard Pelissier, Gauthier Lefevre, Yannick Le-Friec, Christophe Vallee, Gabriele Navarro, Jean-Philippe Reynard
Summary: Phase-Change Memory technology is maturing and attracting interest for future non-volatile memory applications. A protocol using pARXPS technique was developed to measure oxidation thickness on Ge-rich GST alloys, revealing a double oxidation kinetic and influence of nitrogen doping. Analysis was conducted using pARXPS and TEM-EDX techniques.
APPLIED SURFACE SCIENCE
(2022)
Review
Chemistry, Inorganic & Nuclear
Marceline Bonvalot, Christophe Vallee, Cedric Mannequin, Moustapha Jaffal, Remy Gassilloud, Nicolas Posseme, Thierry Chevolleau
Summary: Area selective deposition (ASD) is achieved through super-cycle alternating deposition and etch, with careful optimization of etching step parameters required for optimal selective deposition. Different approaches can be developed to optimize the overall ASD process while limiting process drift and contamination, utilizing complementary selective properties for structure selective deposition.
DALTON TRANSACTIONS
(2022)
Article
Physics, Applied
Naveen Aruchamy, Tony Schenk, Stephanie Girod, Sebastjan Glinsek, Emmanuel Defay, Torsten Granzow
Summary: Solution-deposited ferroelectric films are affected by mechanical stress, and the choice of substrate material plays a crucial role in the ferroelectric response. The study found that the polarization direction and intensity of ferroelectric thin films change under different stress conditions.
JOURNAL OF APPLIED PHYSICS
(2022)
Review
Nanoscience & Nanotechnology
Alvar Torello, Emmanuel Defay
Summary: In this work, the design, performance, and working principles of all electrocaloric prototypes before the year 2021 are reviewed, and hints and guidelines are given for future works to bring the development of these devices one step closer to real applications.
ADVANCED ELECTRONIC MATERIALS
(2022)
Article
Chemistry, Analytical
Veronika Kovacova, Sebastjan Glinsek, Stephanie Girod, Emmanuel Defay
Summary: In this study, thin films of Pb(Sc,Ta)O-3 were prepared using the sol-gel chemical solution deposition method, and very large electric fields were applied using interdigitated top electrodes. The films showed a high temperature variation and the electrocaloric temperature variation could be tuned with stress conditions.
Article
Physics, Applied
Ibrahima Gueye, Gwenael Le Rhun, Olivier Renault, Francois Pierre, Emmanuel Defay, Nicholas Barrett
Summary: We investigated the effect of excessive Pb content on the electrical performance of PZT thin-film capacitors. We found that high Pb excess eliminates the interface layer between PZT and the electrode, reducing the breakdown field. However, the linear dielectric response of the capacitor increases with Pb excess. Our experiments using hard x-ray photoelectron spectroscopy provided direct evidence of a polar but non-ferroelectric PbOx phase in the sol-gel film.
APPLIED PHYSICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Pranab Parimal Biswas, Cosme Milesi-Brault, Alfredo Blazquez Martinez, Naveen Aruchamy, Longfei Song, Veronika Kovacova, Sebastjan Glinsek, Torsten Granzow, Emmanuel Defay, Mael Guennou
Summary: This study investigates the effect of field-induced phase transition on birefringence change in PbZr0.95Ti0.05O3. By using a polycrystalline PbZr0.95Ti0.05O3 film with interdigitated electrodes, changes in birefringence under a polarized microscope were observed. The film in its polar phase behaves like a homogeneous birefringent medium. The change in birefringence has both a fast response and a slower saturation contribution.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Materials Science, Ceramics
Naveen Aruchamy, Stephanie Girod, Sebastjan Glinsek, Emmanuel Defay, Torsten Granzow
Summary: This study compares the fatigue behavior of fully transparent lead zirconate titanate films on fused silica glass or sapphire, respectively, with coplanar interdigitated top electrodes and no bottom electrodes, to that of the same systems in a traditional metal-insulator-metal parallel plate capacitor geometry. The polarization hysteresis decreases rapidly in the latter geometry during bipolar electrical cycling, while systems with coplanar electrodes show no notable fatigue up to 107 cycles. This difference is explained by the columnar microstructure of the films, where the grain boundaries act as trapping sites for oxygen vacancies in coplanar electrode geometries, preventing the formation of agglomerates that cause fatigue through domain wall pinning.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2023)
Article
Chemistry, Physical
Ashwath Aravindhan, Pierre Lheritier, Alvar Torello, Uros Prah, Youri Nouchokgwe, Asmaa El Moul, Xavier Chevalier, Fabrice Domingues Dos Santos, Emmanuel Defay, Veronika Kovacova
Summary: In this study, the electrocaloric effect of P(VDF-TrFE-CFE) film was directly analyzed using infrared imaging. The results showed that P(VDF-TrFE-CFE) exhibited a temperature-independent electrocaloric effect at room temperature. A maximum adiabatic temperature change of 3.58 K was measured during the cooling cycle at a field of 100 V/μm at 30°C. Despite the thermal mass of the substrate, a significant electrocaloric effect was observed in P(VDF-TrFE-CFE) films. This terpolymer composition could be of interest for electrocaloric cooling applications.
JOURNAL OF MATERIOMICS
(2023)
Article
Materials Science, Coatings & Films
Clemence Badie, Heloise Tissot, Beniamino Sciacca, Maissa K. Barr, Julien Bachmann, Christophe Vallee, Gael Gautier, Thomas Defforge, Vincent Astie, Jean-Manuel Decams, Mikhael Bechelany, Lionel Santinacci
Summary: This study focuses on optimizing TiN plasma-enhanced atomic layer deposition by using two different N-sources: NH3 and N-2. Comprehensive physicochemical characterizations were performed to understand the influence of the N-source nature, their dilution in Ar, and the plasma power on the final properties of the deposited layer. It was found that a 1:1 gas ratio of N-sources:Ar mixture, along with low flows (20 sccm), resulted in the highest growth per cycle (GPC) values. The N-2 plasma exhibited slightly slower deposition but acceptable film quality, making it a nonharmful alternative that can be further improved with optimized reactor geometry.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Chemistry, Physical
Uros Prah, Matej Sadl, Alvar Torello, Pierre Lheritier, Veronika Kovacova, Hana Ursic, Emmanuel Defay
Summary: Reliable and accurate characterization of the electrocaloric effect is necessary to understand material properties. A new approach using infrared imaging is proposed to capture the adiabatic electrocaloric effect in ceramic films. The results obtained with this method are validated and compared with other direct and indirect approaches.
Article
Energy & Fuels
Junning Li, Alvar Torello, Youri Nouchokgwe, Torsten Granzow, Veronika Kovacova, Sakyo Hirose, Emmanuel Defay
Summary: Electrocaloric (EC) materials offer a promising alternative to traditional caloric heat pumps, as they can achieve significant temperature changes under the application of electric fields. Researchers have found EC effect in lead-free BaTiO3 multilayer capacitors, which exhibit strong first-order phase transition and improved electrical resistivity by adding a dopant. These findings suggest the potential for designing lead-free caloric cooling prototypes using optimized BaTiO3 capacitors.
JOURNAL OF PHYSICS-ENERGY
(2023)
Article
Engineering, Electrical & Electronic
I. V. Otto, C. Vallee, S. Kal, P. Biolsi
Summary: This paper investigates the selective etching of TaN with low-k dielectric using a low temperature inductively coupled plasma discharge containing an NF3/Ar mixture, based on radical-based etching. Selectivity between TaN and low-k dielectric is achieved by manipulating the chamber condition through the addition of a plasma-deposited SiOx coating to the chamber wall. The coating adds atomic oxygen to the etch processes, decreasing etching of low-k dielectric and allowing selective etching of TaN.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(2023)
Article
Energy & Fuels
Sabrina Unmuessig, David Bach, Youri Nouchokgwe, Emmanuel Defay, Kilian Bartholome
Summary: Caloric cooling systems based on electrocaloric effect offer higher efficiency compared to vapor compression systems. Lead scandium tantalate (PST) materials, which undergo a first-order phase transition, are promising candidates for electrocaloric cooling. In this study, a phenomenological model based on an analytical equation for specific heat capacity is used to describe the behavior of bulk PST material, and its accuracy is validated with experimental data. This model allows for the calculation of essential material properties such as the adiabatic temperature change and isothermal entropy change.
Article
Materials Science, Multidisciplinary
Matej Sadl, Uros Prah, Veronika Kovacova, Emmanuel Defay, Tadej Rojac, Andrej Lebar, Josko Valentincic, Hana Ursic
Summary: In this study, flexible thick-film structures with promising energy storage and electrocaloric cooling capabilities as well as piezoelectric properties are developed, addressing the challenge of sustainable energy management and energy self-sufficiency by managing multiple energy operations in a single device.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
