Article
Materials Science, Multidisciplinary
Bruno Magalhaes, Stefan Engelhardt, Christian Molin, Sylvia E. Gebhardt, Kornelius Nielsch, Ruben Huhne
Summary: While bulk materials research has identified Na0.5Bi0.5TiO3 (NBT)-based compounds as potential candidates for lead-free electrocaloric cooling processes, this study focuses on investigating the feasibility of epitaxial NBT-based thin films for a more detailed analysis of the relationship between composition, microstructure, and functional properties. The thin films exhibited undisturbed epitaxial growth on lattice-matching substrates with columnar microstructure, but showed increased roughness and grain size with thicker films. Dielectric measurements showed a shift in phase transition temperature, reduced permittivity, and increased losses compared to bulk samples.
Article
Materials Science, Multidisciplinary
Kumarswamy Miriyala, Adityanarayan H. Pandey, N. Shara Sowmya, Ajit R. Kulkarni, Venkataramani Narayanan
Summary: In this study, we investigate the structure and properties of the polycrystalline trilayer PNNZT/CTFO/PNNZT composite thin films grown on a substrate using a pulsed laser deposition technique. The individual ferroelectric PNNZT and ferromagnetic CTFO thin films display good functional properties, and the trilayer composite thin films also show significant ferroelectric and magnetic properties. Furthermore, these thin films exhibit a strong magnetoelectric coupling and have potential for device applications.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Marc Stevens, Hanna Pazniak, Alexander Jemiola, Merve Felek, Michael Farle, Ulf Wiedwald
Summary: Pulsed Laser Deposition was used to grow phase pure and epitaxial Cr2AlC MAX phase thin films on MgO(111) and Al2O3(0001). The results demonstrate the potential of this method for the growth of epitaxial MAX phase thin films, with the film thickness affecting the material properties significantly.
MATERIALS RESEARCH LETTERS
(2021)
Article
Crystallography
Laura C. Sauze, Nicolas Vaxelaire, Roselyne Templier, Denis Rouchon, Francois Pierre, Cyril Guedj, Denis Remiens, Guillaume Rodriguez, Marie Bousquet, Florian Dupont
Summary: In this study, 200 nm-thick LiNbO3 films were grown by pulsed laser deposition on congruent LiNbO3 substrates with various crystalline orientations. The influence of the substrate's crystal cut on the physical and chemical properties of the LiNbO3 films was investigated. The results indicate that a standard wafer-based PLD system can be used to grow LiNbO3 thin films with a crystalline quality and a stoichiometry very close to a LiNbO3 monocrystalline substrate.
JOURNAL OF CRYSTAL GROWTH
(2023)
Article
Energy & Fuels
Amr Ghazy, Muhammad Safdar, Mika Lastusaari, Hele Savin, Maarit Karppinen
Summary: The article discusses the current status and challenges of photovoltaic technology and proposes a potential solution to enhance solar cell performance by integrating an upconverting component. It summarizes the design principles, fabrication routes of UC materials, discusses different approaches to integrate UC layers into actual PV device configurations, highlights significant results achieved in the field, presents future prospects, and outlines remaining challenges in this important and intriguing scientific field.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2021)
Article
Crystallography
Dilsom A. Sanchez, Karuna Kara Mishra, Sujoy Saha, Gopalan Srinivasan, Ram S. Katiyar
Summary: The present study demonstrates that PZTFT(x) thin films are multiferroic at room temperature with large magnetoelectric couplings, and these materials may be suitable for use in magnetic sensors and spintronic device applications.
Article
Materials Science, Multidisciplinary
Joe Sakai, Jose Manuel Caicedo Roque, Pablo Vales-Castro, Jessica Padilla-Pantoja, Guillaume Sauthier, Jose Santiso
Summary: In this study, non-doped PbTiO3 thin films were prepared using pulsed laser deposition, and it was found that using a PbO-TiO2 pie-chart target resulted in high-quality films with composition, crystallinity, flatness, and ferroelectric properties almost independent of the areal ratio.
Review
Chemistry, Inorganic & Nuclear
Xiang Zheng, Ranjith Kumar Kankala, Chen-Guang Liu, Shi-Bin Wang, Ai-Zheng Chen, Yong Zhang
Summary: In the past few decades, significant progress has been made in the fabrication of various nanomaterials, particularly in the area of lanthanide-doped upconversion nanocrystals (UCNCs) due to their unique optical properties. However, there is still insufficient understanding of the chemistry behind UCNCs, which plays a crucial role in regulating their luminescent behavior. Further elucidation of UCNC chemistry is necessary for promoting their development and future applications.
COORDINATION CHEMISTRY REVIEWS
(2021)
Article
Physics, Applied
Sijun Luo, Lukas Trefflich, Susanne Selle, Ron Hildebrandt, Evgeny Krueger, Stefan Lange, Jingjing Yu, Chris Sturm, Michael Lorenz, Holger Von Wenckstern, Christian Hagendorf, Thomas Hoeche, Marius Grundmann
Summary: This paper reports the heteroepitaxial growth of (00.1)-oriented Zn2GeO4 thin films on c-plane sapphire substrates using pulsed laser deposition. The thin films exhibit [11.0] Zn2GeO4// [11.0] Al2O3 and [1(1) over bar.0] Zn2GeO4//[1(1) over bar.0] Al2O3 in-plane orientation relationships. The measured properties include a rocking curve full width at half maximum of 0.35 degrees, a direct bandgap of 4.9 +/- 0.1 eV, and a defect-related photoluminescence emission centered at 2.62 eV with a FWHM of 0.55 eV. This study enhances our understanding of the physical properties and potential device application of Zn2GeO4 thin films.
APPLIED PHYSICS LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Ali El Boutaybi, Thomas Maroutian, Ludovic Largeau, Nathaniel Findling, Jean-Blaise Brubach, Rebecca Cervasio, Alban Degezelle, Sylvia Matzen, Laurent Vivien, Pascale Roy, Panagiotis Karamanis, Michel Rerat, Philippe Lecoeur
Summary: The crystal structure and ferroelectric properties of ZrO2 films with thickness ranging from 7 to 42 nm grown on (110)-oriented SrTiO3 substrate with La0.67Sr0.33MnO3 buffer layer are reported. It is confirmed that the films have a tetragonal phase structure and exhibit ferroelectric behavior at thinner thicknesses, but the ferroelectricity diminishes with increasing film thickness.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Chemistry, Physical
M. A. Khan, L. Braic, Y. AlSalik, H. Idriss
Summary: Monolithic integration of metal oxide thin films with conventional semiconductors such as silicon and germanium allows for new functionalities in semiconductor devices. Using pulsed laser deposition (PLD), epitaxial strontium titanate (STO) films were grown on Ge (001) single crystal, achieving a sharp interface without interfacial amorphous oxide layer by optimizing surface preparation and deposition conditions. Factors such as Ge(001) surface substrate cleaning, growth temperature, oxygen partial pressure, and laser energy density are discussed for their effects on STO film growth, with the presence of O-2 leading to growth on (100) and (110) planes.
APPLIED SURFACE SCIENCE
(2021)
Article
Physics, Applied
S. Funada, D. Kan, K. Kuwano, Y. Shiota, R. Hisatomi, T. Moriyama, Y. Shimakawa, T. Ono
Summary: In this study, the temperature dependence of the ferrimagnetic resonance and damping constant of Gd3Fe5O12 films were investigated. The results show that the damping constant is an order of magnitude smaller than those of other ferrimagnetic metals reported so far, highlighting the potential of Gd3Fe5O12 films in ultralow-power spintronic applications.
APPLIED PHYSICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Jun Kasahara, Tsukasa Katayama, Akira Chikamatsu, Yosuke Hamasaki, Tetsuya Hasegawa
Summary: In this study, the hexagonal Gd phase of rare-earth iron oxide was synthesized via epitaxial stabilization, resulting in a highly crystalline film. The film exhibited weak ferromagnetism with a lower Neel temperature compared to previously reported films.
Article
Physics, Applied
Dong Gao, Zheng Peng, Ningbin Zhang, Yunfei Xie, Yucong Yang, Weihao Yang, Shuang Xia, Wei Yan, Longjiang Deng, Tao Liu, Jun Qin, Xiaoyan Zhong, Lei Bi
Summary: This study reports the structure, magneto-optical, and transport properties of epitaxial Mn3Sn thin films fabricated by pulsed laser deposition (PLD). The anomalous Hall effect and longitudinal magneto-optical Kerr effect of the epitaxial films were found comparable to Mn3Sn single crystals. The work paves the way for future device applications of high-quality Mn3Sn epitaxial thin films.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Physical
B. Magalhaes, S. Engelhardt, C. Molin, S. E. Gebhardt, K. Nielsch, R. Huehne
Summary: The study investigated the correlation between structural parameters and the electrocaloric effect in lead-free epitaxial Ba1-xSrxTiO3 (BSTO) thin films. It was found that as the Sr content increased, the temperature of maximum permittivity decreased, and a relaxor-like behavior was observed.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Ayse Suenbuel, David Lehninger, Raik Hoffmann, Ricardo Olivo, Aditya Prabhu, Fred Schoene, Kati Kuehnel, Moritz Doellgast, Nora Haufe, Lisa Roy, Thomas Kaempfe, Konrad Seidel, Lukas M. Eng
Summary: This study investigates the influence of various thicknesses of hafnium-zirconium-oxide (HZO) in metal-ferroelectric-metal (MFM) capacitors on the reliability of ferroelectric devices under different operating temperatures and electric fields. The results show that the 7 nm thick HZO exhibits promising endurance and retention performance under high temperature and high load conditions, indicating potential applications.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Faizan Ali, Tarek Ali, Akmal Abbas, David Lehninger, Muhammad Faisal Iqbal, Mohammed M. Fadhali, Ibrahim A. Shaaban, Malte Czernohorsky, Konrad Seidel, Thomas Kaempfe
Summary: This study investigates the frequency-dependent polarization and phase switching of Si-doped HfO2-based metal-dielectric-metal capacitors with ferroelectric and antiferroelectric-like thin films, respectively. The Kolmogorov-Avrami-Ishibashi (KAI) and nucleation-limited switching models are used to analyze the polarization switching of Si-doped HfO2 ferroelectric thin films. Additionally, the energy storage properties of Si-doped HfO2 antiferroelectric thin films are examined over a wide measurement frequency range (50 Hz-100 kHz). The results show that both energy storage density and efficiency decrease with increasing frequency, while energy loss increases.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Engineering, Electrical & Electronic
Maximilian Lederer, Ricardo Olivo, Nandakishor Yadav, Sourav De, Konrad Seidel, Lukas M. Eng, Thomas Kaempfe
Summary: This paper presents a semi-empirical, SPICE-compatible and computationally efficient compact model for describing ferroelectric capacitors (Fe-CAP). Inspired by the Jiles-Atherton model for ferromagnets, this model requires significantly less computational effort than other state-of-the-art models. It accurately calculates the memory window and hysteresis of Fe-CAP for arbitrary signals.
SOLID-STATE ELECTRONICS
(2023)
Article
Chemistry, Physical
Hao Li, Yingjie Zhao, Ilya Kolesnikov, Shiqing Xu, Liang Chen, Gongxun Bai
Summary: This study successfully developed rare earth ions-doped Ba2LaF7 nanocrystals as the core material in a multi-functional system for photothermal therapy. Optical temperature measurement based on fluorescence intensity ratio improved sensitivity, and the nanocrystals showed a good photothermal response to laser pumping power and could be used for photothermal imaging.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Physics, Applied
M. Lederer, C. Mart, T. Kampfe, D. Lehninger, K. Seidel, M. Czernohorsky, W. Weinreich, B. Volkmann, L. M. Eng
Summary: The mechanism of nanoscopic domain switching in ferroelectric hafnium oxide and its implications for antiferroelectric-like behavior as well as for the wake-up effect are still under extensive discussion. Understanding this mechanism is crucial for numerous applications such as piezoelectric actuators, pyroelectric sensors, and nonvolatile memory devices. This article utilizes electrical and physical analysis methods to characterize ferroelectric hafnium oxide at both nanoscopic and macroscopic scales. Evidence of nanoscopic domains is observed through transmission Kikuchi diffraction, and combined with macroscopic Preisach density measurements, it is strongly suggested that antiferroelectric-like behavior and wake-up are governed by ferroelastic switching involving 90 degrees domain wall motion. Based on these findings, the material stack can be optimized to enhance microelectronic applications based on HfO2.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Y. Raffel, R. Olivo, M. Simon, L. Vieler, R. Hoffmann, S. De, T. Kaempfe, K. Seidel, M. Lederer
Summary: While semiconductor-based spin qubits have high fidelities, their coherence time is limited by charge noise. This study explores low frequency analysis methods to understand the relationship between interface trap densities, temperature, and observed noise levels. The results show a strong temperature dependence of the interface trap density and good agreement between charge pumping and conductance-based methods. The study also highlights different temperature dependent trends in flicker noise, suggesting the need for further device optimization.
APPLIED PHYSICS LETTERS
(2023)
Article
Automation & Control Systems
Vivek Parmar, Franz Mueller, Jing-Hua Hsuen, Sandeep Kaur Kingra, Laleni Nellie, Yannick Raffel, Maximilian Lederer, Alptekin Vardar, Konrad Seidel, Taha Soliman, Tobias Kirchner, Tarek Ali, Stefan Duenkel, Sven Beyer, Tian-Li Wu, Sourav De, Manan Suri, Thomas Kaempfe
Summary: Harnessing multibit precision in NVM-based synaptic core can accelerate MAC operation of DNN. However, NVM-based synaptic cores suffer from the trade-off between bit density and performance, posing a severe bottleneck.
ADVANCED INTELLIGENT SYSTEMS
(2023)
Article
Automation & Control Systems
Xunzhao Yin, Franz Mueller, Qingrong Huang, Chao Li, Mohsen Imani, Zeyu Yang, Jiahao Cai, Maximilian Lederer, Ricardo Olivo, Nellie Laleni, Shan Deng, Zijian Zhao, Zhiguo Shi, Yiyu Shi, Cheng Zhuo, Thomas Kaempfe, Kai Ni
Summary: Content addressable memory (CAM) is widely used due to its parallel pattern matching capability. To improve performance and area efficiency, a novel ultracompact 1FeFET CAM design is proposed, which enables parallel associative search and in-memory hamming distance calculation. The design also includes a multibit CAM for exact search using the same CAM cell.
ADVANCED INTELLIGENT SYSTEMS
(2023)
Article
Engineering, Electrical & Electronic
Sukhrob Abdulazhanov, Quang Huy Le, Dang Khoa Huynh, Defu Wang, David Lehninger, Thomas Kaempfe, Gerald Gerlach
Summary: This paper presents the broadband microwave characterization of a metal-ferroelectric-metal (MFM) thin film varactor made of ferroelectric hafnium zirconium oxide (Hf0.5Zr0.5O2), covering a frequency range from 1 kHz to 0.11 THz. The varactor, integrated into the back-end-of-line (BEoL) of 180 nm CMOS technology, shows a maximum tunability of 15% at low frequencies and 10% at 110 GHz. The study demonstrates that ferroelectric HfO2 thin films with good back-end-of-line compatibility can support large scale integration, enabling potential applications in the mmWave and THz frequency range.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Patrick James Artz, Quang Huy Le, Dang Khoa Huynh, Philipp Scholz, Thomas Kampfe, Steffen Lehmann, Thomas Mausolf, Friedel Gerfers
Summary: This article presents the design and characterization of a fully differential D-band LNA with a gain range of 9.0-18.0 dB at 153.5 GHz and a 3-dB bandwidth of 10.8 GHz. The measured NF using the cold-noise source method is 7.9 dB, achieved through accurate NF measurements with a source tuner for noise parameter extraction. The back gate control of the 22-nm FDSOI technology enables a passive gain control range of 9 dB, reducing NF and compression point degradation while scaling the power consumption.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2023)
Article
Materials Science, Multidisciplinary
Hongbin Zhang, Jiasong Zhang, Renguang Ye, Shiqing Xu, Gongxun Bai
Summary: In this study, we successfully prepared a series of cerium sulfide colorant powders using the hydrothermal method and chemical doping engineering. The effect of La3+ doping concentration on the crystal structure and spectral properties of gamma-Ce2S3 was investigated. The prepared light-emitting device can emit red light with a high degree of purity, which is advantageous for information display and the growth of certain plants. Based on the findings, cerium sulfide colorant powders have broad applications in optoelectronics.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Yongjie Yu, Kun He, Haibo Xu, Zhen Xiao, Liang Chen, Shiqing Xu, Gongxun Bai
Summary: Flexible electroluminescent devices with phosphor layers are fabricated by a solution method in this study, using polyvinylidene difluoride as the dielectric layer and ionic hydrogels as electrodes. These devices can be effectively driven even at an operating frequency of 0.1 kHz and exhibit multi-color emission. The results demonstrate the promising potential of these developed devices for flexible optoelectronics.
Article
Chemistry, Multidisciplinary
Yanbang Lian, Congcong Wang, Yu Meng, Junqiang Dong, Jianbin Zhang, Shiqing Xu, Gongxun Bai, Jianbo Gao
Summary: In this study, two-dimensional heterostructures with bismuth selenide and tungsten selenide nanosheets were prepared as photothermal nanoagents. The near-infrared photothermal conversion of the selenide heterostructure nanosheets reached up to 40.75% under 808 nm excitation. The experiments with mice demonstrated low toxicity and high biocompatibility of the heterostructure nanosheets, both in vitro and in vivo. The developed selenide nanosheets have great potential application in cancer therapy.
Proceedings Paper
Engineering, Electrical & Electronic
M. Rack, L. Nyssens, Q. H. Le, D. K. Huynh, T. Kaempfe, J. -P. Raskin, D. Lederer
Summary: This paper describes the design and implementation of a 113.5-127 GHz D-band LNA using GlobalFoundries' 22 nm FD-SOI technology. The proposed design achieves 6.6 dB of minimal noise-figure in-band for a peak gain of 17.5 dB at its nominal bias for a 27.5 mW power-consumption using a low supply voltage of 0.75 V, and can achieve an NF down to 6.1 dB and gain up to 19.1 dB in a high-performance state. It also introduces the capability of the LNA to be configured as a variable-gain device by utilizing the back-gate bias node of the 22FDX (R) technology.
2023 18TH EUROPEAN MICROWAVE INTEGRATED CIRCUITS CONFERENCE, EUMIC
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Quang Huy Le, Dang Khoa Huynh, Steffen Lehmann, Zhixing Zhao, Christoph Schwan, Thomas Kaempfe, Matthias Rudolph
Summary: This paper presents the modeling and analysis of high-frequency noise in 22-nm FDSOI CMOS technology. Experimental noise parameters up to 170 GHz are extracted for a multi-finger n-channel transistor using the tuner-based method. The applicability of the Pucel (PRC) noise model for predicting the noise characteristics of 22-nm FDSOI technology from low frequencies to D-band frequencies is validated. Additionally, the extraction and analysis of model parameters with respect to drain current at 94 GHz frequency are demonstrated.
2023 IEEE 23RD TOPICAL MEETING ON SILICON MONOLITHIC INTEGRATED CIRCUITS IN RF SYSTEMS
(2023)
