Article
Chemistry, Physical
A. C. Garcia-Wong, D. Pilloud, S. Bruyere, D. Mangin, S. Migot, J. F. Pierson, F. Capon
Summary: In this study, vanadium nitride (VN) thin films were deposited on Al substrates by reactive magnetron sputtering, and thermochromic VO2 films were obtained by air oxidation. X-ray diffraction and Raman spectrometry showed that VO2 and V2O5 are the only phases produced during the oxidation process.
JOURNAL OF MATERIOMICS
(2021)
Article
Chemistry, Physical
Dasom Wang, Jaeyeong Bae, Hyung-Jin Choi, Seung-Hyub Baek, Seungwan Woo, Donghee Park, Won Jun Choi
Summary: This study reports on the modification of electrical properties of amorphous vanadium oxide (a-VOx) thin film thermistor by growth temperature and its effects on the performances of a cooler-free microbolometer. The sheet resistance of the a-VOx thin films decreases with increasing growth temperature, attributed to the increase of oxygen vacancies. The temperature dependence of resistance and activation energy of the a-VOx films also show distinct changes with growth temperature.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Engineering, Electrical & Electronic
Ozer celik, Memed Duman
Summary: The noise properties of a-VWOx thin films deposited by reactive DC sputtering were investigated for microbolometer applications. It was found that there is no random telegraph switching noise in the deposited films, and the material was deemed suitable for microbolometer applications. The effects of electrode material and structure on contact resistance, as well as different currents and electrode structures on 1/f noise measurements, were also analyzed.
SENSORS AND ACTUATORS A-PHYSICAL
(2022)
Article
Materials Science, Coatings & Films
Yuta Miyatake, Yukito Ozawa, Kunio Okimura, Toshihiro Nakanishi
Summary: This study reports on the realization of thin polyimide films on which phase transition vanadium dioxide (VO2) films grow. Stand-alone VO2/ZnO/polyimide layered films were fabricated, exhibiting insulator-metal transition (IMT) and high flexibility. The proposed structure has the potential to be used in active metasurfaces for controlling terahertz waves with low reflection loss.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2022)
Article
Nanoscience & Nanotechnology
Min-Han Lee, Yoav Kalcheim, Javier del Valle, Ivan K. Schuller
Summary: The study demonstrates a high-vacuum gas evolution technique to precisely control oxygen concentrations in VOX thin films. Through detailed structural investigations, optimal stoichiometry is achieved and stabilized. This technique provides new pathways to strategically tune the oxygen stoichiometry in complex oxides and offers insights into the phase stability of VOX thin films.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Materials Science, Multidisciplinary
Arnaud le Febvrier, Davide Gambino, Fabien Giovannelli, Babak Bakhit, Simon Hurand, Gregory Abadias, Bjorn Alling, Per Eklund
Summary: This article reports the results of a study on nonstoichiometric CrN1+?? thin films, showing a transition from n-type to p-type behavior and changes in lattice parameter and Seebeck coefficient with varying nitrogen concentration. The presence of Cr vacancies and N2 dumbbells, possibly in combined configurations, was found to explain the experimental trends. This research opens up possibilities for controlling the semiconducting behavior of CrN and its integration in energy-harvesting thermoelectric devices.
Article
Chemistry, Physical
Juliusz Chojenka, Arkadiusz Zarzycki, Marcin Perzanowski, Michal Krupinski, Tamas Fodor, Kalman Vad, Marta Marszalek
Summary: We study the magnetic properties of thin iron films on nanoporous titanium oxide templates and analyze their dependence on nanopore radius. We compare these results with a continuous iron film of the same thickness and investigate the evolution of magnetic properties after annealing. We find that the M(H) loops of the films consist of two magnetic phases from the iron layer and iron oxides formed at the titanium oxide/iron interface. Deconvolution of hysteresis loops helps extract information for each magnetic phase. We also explore the magnetic interactions between the phases and observe the magnetic hardening effect induced by the nanopores. The ZFC-FC measurements show a disordered glass state below 50 K, likely due to iron oxide formation and short-range magnetic order at the titanium oxide-iron interface.
Article
Engineering, Electrical & Electronic
V. R. Sreelakshmi, A. Anu Kaliani, M. Jithin
Summary: VO-MO mixed oxide thin films with different compositions were prepared using thermal evaporation technique. The films showed good thermochromic and reversible properties, with VO50% MO50% exhibiting the best transition temperature near room temperature. All the three films exhibited metamaterial properties in a small range of temperatures and showed good photocatalytic performance on dye degradation under direct sunlight. The VO50% MO50% film showed the highest photocatalytic performance among the three compositions.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2023)
Article
Chemistry, Multidisciplinary
Maxime Van den Bossche, Jacek Goniakowski, Claudine Noguera
Summary: Ultra-thin alumina films coated on aluminum alloy surfaces are important for various applications, but their structural and stability characteristics are still not well understood. Research indicates that on NiAl(100) substrates, observed theta-alumina films correspond to thermodynamic equilibrium, rather than being influenced by kinetic effects during alloy oxidation and film growth.
Article
Chemistry, Physical
Maria Basso, Elena Colusso, Chiara Carraro, Curran Kalha, Aysha A. Riaz, Giada Bombardelli, Enrico Napolitani, Yu Chen, Jacek Jasieniak, Laura E. Ratcliff, Pardeep K. Thakur, Tien-Lin Lee, Anna Regoutz, Alessandro Martucci
Summary: Pulsed excimer laser annealing is used to crystallize VO2 thin films at room temperature, achieving comparable thermochromic properties to furnace annealing with shorter annealing time and reduced energy consumption.
APPLIED SURFACE SCIENCE
(2023)
Article
Nanoscience & Nanotechnology
Martando Rath, Moussa Mezhoud, Oualyd El Khaloufi, Oleg Lebedev, Julien Cardin, Christophe Labbe, Fabrice Gourbilleau, Vincent Polewczyk, Giovanni Vinai, Piero Torelli, Arnaud Fouchet, Adrian David, Wilfrid Prellier, Ulrike Luders
Summary: This study investigates the chemical stability of SrVO3 (SVO), a potential replacement for conventional ITO in the new generation of TCO materials. By subjecting the SVO thin films to heat treatments in the range of 150-250 degrees Celsius, the researchers are able to accelerate the natural aging process and observe changes in the structural, electrical, and optical properties. The results indicate surface oxidation at low annealing temperatures and the destruction of the perovskite phase at temperatures above 200 degrees Celsius. The goal of this study is to understand the thermal degradation and long-term stability issues of vanadate-based TCOs and identify technologically viable solutions for their application.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Anchal Rana, Aditya Yadav, Govind Gupta, Abhimanyu Rana
Summary: We present an efficient method of growing infrared (IR) sensitive mixed phase of V7O16 and V2O5 thin films at low temperatures. The mixed phase can be stabilized by annealing amorphous VxOy at 300-400 degrees C, and is fully converted into V2O5 after annealing at 450 degrees C. The optical transmission of the films increases with the content of V2O5, while the electrical conductivity and optical bandgap decrease. The IR sensitivity is explained by plasmonic absorption by the V7O16 degenerate semiconductor.
Article
Materials Science, Ceramics
Mohammed Bouzbib, Janos Rohonczy, Katalin Sinko
Summary: This study investigates the impact of chemical substances on the structure, surface morphology, and material properties of vanadium oxide thin films. The focus is on the effects of initial materials and various additives using the sol-gel chemistry principle. The objectives are to optimize the chemical conditions for the preparation of V5+-containing layers and to examine the controllability of the V4+/V5+ ratios. Atomic and bond structures are analyzed using V-51 MAS NMR, IR, and UV spectroscopies, while supramolecular structures are determined through SEM, EDX, and GIXRD techniques.
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Xitao Guo, Yonghao Tan, Yupei Hu, Zainab Zafar, Xin Liu, Lin Feng, Jijun Zou
Summary: VO2 thin films composed of irregularly shaped microplates have been successfully synthesized using V2O5 as a precursor via vapor transport technique. These films exhibit high crystal quality of monoclinic VO2 phase and show interesting phase transition behavior and infrared response.
NEW JOURNAL OF CHEMISTRY
(2022)
Article
Materials Science, Multidisciplinary
Minji Jeong, Jihye Park, Young Joon Cho, Hyo Sik Chang
Summary: Atomic-layer-deposited MoOx was investigated as a hole-selective layer in Si heterojunction solar cells. The introduction of ultrathin ALD-Al2O3 significantly improved the passivation of interface defects in the ALD-MoOx/Si structure. The carrier lifetime and implied open-circuit voltage were increased through this approach.
Article
Nanoscience & Nanotechnology
Alessandro R. Mazza, Qiyang Lu, Guoxiang Hu, Haoxiang Li, James F. Browning, Timothy R. Charlton, Matthew Brahlek, Panchapakesan Ganesh, Thomas Zac Ward, Ho Nyung Lee, Gyula Eres
Summary: We report on the mechanism of hydrogen-induced topotactic phase transitions in perovskite oxides using La0.7Sr0.3MnO3 as an example. The hydrogenation causes lattice expansion and changes in electronic structure, leading to a metal-insulator transition. The ordering of oxygen vacancies induces a phase transition from perovskite to brownmillerite. This study reveals the significant impact of hydrogen-induced oxygen vacancy formation on the properties of perovskite oxides.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Nanoscience & Nanotechnology
Deepankar Sri Gyan, Hyeon Jun Lee, Youngjun Ahn, River B. Carson, Jerome Carnis, Tae Yeon Kim, Sanjith Unithrattil, Jun Young Lee, Sae Hwan Chun, Sunam Kim, Intae Eom, Minseok Kim, Sang-Youn Park, Kyung Sook Kim, Ho Nyung Lee, Ji Young Jo, Paul G. Evans
Summary: Above-bandgap femtosecond optical excitation leads to structural responses in a ferroelectric/dielectric BaTiO3/CaTiO3 superlattice, with a net lattice expansion consistent with depolarization-field screening. The magnitude of expansion in BaTiO3 layers is larger than the contraction in CaTiO3, showing a new direction for manipulation of polarization in the component layers. The differences in depolarization-field-screening-driven strain in the BaTiO3 and CaTiO3 components can be attributed to the oxygen octahedral rotation patterns at the interfaces.
ADVANCED ELECTRONIC MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Youngkyoung Ha, Jinho Byun, Jaekwang Lee, Jaeseok Son, Younghak Kim, Shinbuhm Lee
Summary: By alloying SrVO3 with BaVO3, a higher infrared transmittance and lower resistivity can be achieved, resulting in better electromagnetic shielding effects. The characteristics of the alloy are realized through breaking the symmetry of oxygen octahedra, electron localization, and stronger correlation effects, providing a new strategy for designing super-broad-band transparent conductors.
Article
Chemistry, Multidisciplinary
Dongwon Shin, Sangmoon Yoon, Sehwan Song, Sungkyun Park, Ho Nyung Lee, Woo Seok Choi
Summary: This study demonstrates the substantial enhancement of the Curie temperature in epitaxial LaCoO3 thin films by changing the crystallographic orientation. The modification of crystal-field energy and charge transfer between Co and O orbitals leads to a considerable enhancement of the ferromagnetic properties, despite the identical nominal degree of epitaxial strain.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Chemistry, Physical
Tiantian Zhang, T. Yilmaz, E. Vescovo, H. X. Li, R. G. Moore, H. N. Lee, H. Miao, S. Murakami, M. A. McGuire
Summary: Topological semimetals are a frontier of quantum materials. In multiband electronic systems, topological band crossings can form closed curves, known as nodal lines. Recently, six endless nodal lines and two nodal rings were found in nonmagnetic Ni3In2S2, leading to a large magnetoresistance.
NPJ COMPUTATIONAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Youngkyoung Ha, Shinbuhm Lee
Summary: This study investigates the transparent conducting properties of SrMoO3 epitaxial films grown on Al2O3 substrate. The results show that these films have low sheet resistance, high transmittance, and high conductivity, and they remain thermally stable in extreme environments.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Dongha Kim, Yuri Jeon, Judith Louise MacManus-Driscoll, Shinbuhm Lee
Summary: BaInO2.5 epitaxial films exhibit remarkable solid-state catalytic hydrogen sponge capacity at low temperature, with three orders of magnitude higher hydrogen ion conductivity compared to sintered pellets. The films can store hydrogen ions near InO4 tetrahedral layers without destroying the parent framework, making them ideal for neuromorphic devices.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Qingteng Zhang, Gang Wan, Vitalii Starchenko, Guoxiang Hu, Eric M. Dufresne, Hua Zhou, Hyoungjeen Jeen, Irene Calvo Almazan, Yongqi Dong, Huajun Liu, Alec R. Sandy, George E. Sterbinsky, Ho Nyung Lee, P. Ganesh, Dillon D. Fong
Summary: The intermittent behavior of point defects in oxide heterostructures has been discovered using X-ray photon correlation spectroscopy. The local fluctuations between ordered phases in strained SrCoOx with different stability of oxygen vacancies are found to be modulated by the interaction energy between oxygen ions/vacancies and epitaxial strain. This study reveals the influence of defect dynamics on material functionality and opens new avenues for engineering the dynamical response of functional materials in neuromorphic and electrochemical applications.
ADVANCED MATERIALS
(2023)
Article
Physics, Applied
Dongsu Kim, Chong-Myeong Song, Su Jin Heo, Goeun Pyo, Dongha Kim, Ji Hwan Lee, Kyung-Ho Park, Shinbuhm Lee, Hyuk-Jun Kwon, Jae Eun Jang
Summary: To enhance the performance of nonvolatile charge trap flash memory devices, we proposed an in situ Hf0.5Zr0.5O2 (HZO)/HfO2/Al2O3 stacked structure compatible with Si and based on all atomic layer deposition. The stable charge trap operation is achieved through appropriate bandgap difference between Al2O3 and HfO2. The HZO as a blocking layer improves the memory performance by its specific polarization effect, exhibiting high polarization characteristics and good retention capability, fast response times, and strong durability.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Dongha Kim, Jingyeong Jeon, Joon Deok Park, Xiao-Guang Sun, Xiang Gao, Ho Nyung Lee, Judith L. MacManus-Driscoll, Deok-Hwang Kwon, Shinbuhm Lee
Summary: In this study, TiO2(B) is used as a promising material for battery electrodes due to its pseudocapacitive, unidimensional, rapid ion channels. The alignment of these channels is achieved by growing TiO2(B) films with the help of an isostructural VO(2)(B) template layer. The resulting electrode exhibits a supercapacitive behavior, high charge-discharge reproducibility, and excellent stability, suggesting the potential for miniaturizing all-solid-state nanobatteries in self-powered integrated circuits.
Article
Materials Science, Multidisciplinary
Youngkyoung Ha, Judith L. MacManus-Driscoll, Shinbuhm Lee
Summary: Using a one-step process, we successfully designed vertically aligned nanocomposite conducting films with high transparency across a super-broad wavelength range. The films consist of vertically aligned transparent Ba3V2O8 nanocolumns with lateral widths of around 100 nm, which provide high transmittance for all incident light, even at a 4-pm wavelength. The conducting SrVO3 matrix in the films also exhibits low resistivity at room temperature. Scanning transmission electron microscopy, scattering scanning nearfield infrared microscopy, and X-ray diffraction revealed that the Ba3V2O8 nanocolumns undergo spontaneous phase separation in the SrVO3 matrix via self-assembled epitaxial nucleation. This work presents a promising platform for next-generation optoelectronics.
Article
Materials Science, Multidisciplinary
Robert G. Moore, Satoshi Okamoto, Haoxiang Li, William R. Meier, Hu Miao, Ho Nyung Lee, Makoto Hashimoto, Donghui Lu, Elbio Dagotto, Michael A. McGuire, Brian C. Sales
Summary: This study investigates the complex interplay between magnetic moments and topological electronic structures in materials with kagome lattices through experiments and calculations. The results show that the variation of magnetic moments may affect the energy of topological surface bands, but no gap opening is observed during the temperature-dependent magnetic phase transition.
Article
Nanoscience & Nanotechnology
Jie Zhang, Yun-Yi Pai, Jason Lapano, Alessandro R. Mazza, Ho Nyung Lee, Rob G. Moore, Benjamin J. Lawrie, T. Zac Ward, Gyula Eres, Valentino R. Cooper, Matthew Brahlek
Summary: Understanding band alignment and charge transfer at complex oxide interfaces is crucial for utilizing their diverse functionality. This study investigates and validates the charge transfers at oxide/oxide semiconductor/metal interfaces, and proposes a method for predicting band alignment and charge transfer in ABO(3) perovskites.
Article
Engineering, Electrical & Electronic
Dongha Kim, Wook Ki Jung, Shinbuhm Lee
Summary: By treating the surface of the polyethylene terephthalate substrate, ultra-thin, clean, wide, and flexible SC SrRuO3 membranes were achieved, showing potential for use in future electronic and energy devices.
NPJ FLEXIBLE ELECTRONICS
(2022)