Article
Chemistry, Multidisciplinary
Yuzhu Wang, Peng Wang, Hao Wang, Bingqian Xu, Hui Li, Mo Cheng, Wang Feng, Ruofan Du, Luying Song, Xia Wen, Xiaohui Li, Junbo Yang, Yao Cai, Jun He, Zhenxing Wang, Jianping Shi
Summary: An ingenious space-confined chemical vapor deposition strategy was used to synthesize atomically thin non-layered epsilon-Fe2O3 single crystals and revealed the room-temperature long-range ferrimagnetic order. Strong ferroelectricity and its switching behavior were discovered in atomically thin epsilon-Fe2O3, along with an anomalous thickness-dependent coercive voltage. The robust room-temperature magnetoelectric coupling was uncovered by controlling the magnetism with an electric field, demonstrating the multiferroic feature of atomically thin epsilon-Fe2O3. This work represents a substantial leap in the controllable synthesis of 2D multiferroics with robust magnetoelectric coupling, and also paves the way for practical applications in low-energy-consumption electric-writing/magnetic-reading devices.
ADVANCED MATERIALS
(2023)
Article
Materials Science, Ceramics
Mei Ying Liu, Tu Lai Sun, Ting Ting Gao, Zhi Ping Bian, Zhen Lin Luo, Xiao Qiang Liu, Xiang Ming Chen
Summary: This study enhances the ferroelectricity of SmFeO3 thin films by introducing a CaTiO3 blocking layer, and verifies the room-temperature ferroelectricity and magnetoelectric coupling effect.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2022)
Article
Materials Science, Ceramics
Lu Yin, Chuanbin Wang, Qiang Shen
Summary: The growth process of LSMZO films and the effect of adding Zn element on their properties were studied. The results show that increasing Zn content will decrease the Curie temperature and metal-insulator transition temperature of LSMZO, and increase the coercive field and room-temperature resistivity. Analysis of the fraction of Mn3+ and Mn4+ shows that Zn2+ substitution at the Mn site weakens the double-exchange interaction by increasing the Mn4+ fraction. In addition, ionic radius mismatch and substrate-induced strain also affect the performance of LSMZO. Most importantly, enhanced magnetic disorder in the LSMZO (y = 10%) film leads to an increase in intrinsic magnetoresistance around room temperature, and a large magnetoresistance of 18.4% is obtained at 0.3 T and 280 K in this sample.
CERAMICS INTERNATIONAL
(2023)
Article
Chemistry, Physical
Joost W. C. Reinders, Cristina Roldan-Carmona, Henk J. Bolink, Francisco Palazon
Summary: This study reports on the fabrication of Mg(3)Bi(2) thin films under Mg-rich and Mg-poor conditions and demonstrates that Mg-deficient films show p-type conduction behavior with high power factor and thermoelectric figure of merit, while increasing the amount of Mg enables the formation of Mg-rich Mg3Bi2 films with n-type conduction and higher power factor and thermoelectric figure of merit at lower temperatures.
ACS APPLIED ENERGY MATERIALS
(2023)
Article
Chemistry, Physical
Pamella Vasconcelos Borges Pinho, Alain Chartier, Denis Menut, Antoine Barbier, Myrtille O. J. Y. Hunault, Philippe Ohresser, Cecile Marcelot, Benedicte Warot-Fonrose, Frederic Miserque, Jean-Baptiste Moussy
Summary: A quantitative link between chromium content, Fe2+/Fe3+ site-occupation and macroscopic physical properties of Fe3-xCrxO4 thin films is established using spectroscopic measurements and theoretical simulations. It is found that increasing chromium content delays the transition of Fe3-xCrxO4 thin films from inverse to normal spinel configuration and promotes collinear spin structure. The unique cation distribution in these thin films favors electron hopping and results in a smaller electronic band gap.
APPLIED SURFACE SCIENCE
(2023)
Article
Crystallography
Feifei Lan, Rui Zhou, Ziyue Qian, Yuansha Chen, Liming Xie
Summary: In this study, Fe3O4 thin films with room-temperature ferrimagnetism were successfully grown using a simple chemical vapor deposition method. The films maintained good magnetic properties even at thicknesses as low as 4 nm. Various analysis techniques were used to study the structure and quality of the films, and it was found that the saturation magnetization was higher than that of bulk materials and the Verwey transition was observed. This work provides a new method for synthesizing ultrathin films with ferrimagnetic properties for applications in electronics, spintronics, and memory devices.
Article
Physics, Applied
Jing Wang, Weiyuan Wang, Jiyu Fan, Huan Zheng, Hao Liu, Chunlan Ma, Lei Zhang, Wei Tong, Langsheng Ling, Yan Zhu, Hao Yang
Summary: In this study, a method for growing large-area 2D ferromagnetic single-crystal thin films was reported. The thin films were found to have high-quality epitaxy and smooth surfaces, with a high Curie temperature and an easy-magnetization axis in the film plane. The magnetic behavior of the thin films followed the mean-field model rather than the 3D Heisenberg model, in contrast to the bulk counterpart.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Dong Lin, Jing-Ze Yang, Jian-Rui Cheng, Xu-Chu Deng, Yu-Shan Chen, Ping-Ping Zhuang, Tie -Jun Li, Jing Liu
Summary: Nitrogen-doped indium tin oxide (ITON) thin films were deposited through radio frequency magnetron sputtering with different thicknesses. The crystallinity, surface morphologies, and chemical compositions of the thin films were influenced by the film thickness and subsequently affected the conductivity. Ultrathin ITON thin films were used as channels, while an 85-nm-thick ITON was used as the source/drain electrodes to fabricate thin-film transistors. The optimized device fabricated at room temperature showed a threshold voltage of -2.5 V and a field-effect mobility of 10.31 cm(2)/(V center dot s).
Article
Chemistry, Physical
Ga Hye Kim, Seung-Han Kang, Jong Min Lee, Minki Son, Jiyong Lee, Hyungseok Lee, In Chung, Jaehyun Kim, Yong-Hoon Kim, Kyunghan Ahn, Sung Kyu Park, Myung-Gil Kim
Summary: This study presents the fabrication of high-performance complementary metal oxide-semiconductor (CMOS) circuits using nanocrystalline tellurium (nc-Te) and amorphous-indium gallium zinc oxide (aIGZO) thin-film transistors (TFTs) deposited at room temperature. The use of facile polyethyleneimine (PEI) surface treatment enables high-performance TFTs with good mobility and Ion/Ioff ratio, and the integration of nc-Te and aIGZO TFTs allows the fabrication of various CMOS circuits. The nc-Te on a PEI-treated surface offers a general route to producing stable p-type semiconductors compatible with standard CMOS processing and large-scale on-chip device applications.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Marijn W. van de Putte, Mark Huijben
Summary: To enable miniaturized thermoelectric energy generation devices for wireless sensors, high-quality thin film architectures are needed. This study explores the impact of epitaxial alignment between the orthorhombic SnSe crystal structure and the orthorhombic DyScO3 substrate. The achieved (100)-oriented single crystalline SnSe thin films exhibit the formation of two domain types, and show a sudden increase in electrical conductivity above 400 K. The epitaxial alignment enhances thermoelectric performance and enables the realization of miniaturized TEG devices.
APPLIED SURFACE SCIENCE
(2023)
Article
Materials Science, Ceramics
Yuan -Wen Hsiao, Shang-Ren Chee, Hsuan-Ta Wu, Chuan-Feng Shih
Summary: This research investigates the transport and thermoelectric behaviors of CZTSSe thin films. Both p-type and n-type films were successfully synthesized to comprehensively study the characteristics of CZTS. The conductivity and carrier concentration increased with higher Cu contents, changing the conducting type from p-type to n-type. The band gap decreased and the full width at half maximum increased with increased Cu content. The proposed n-type CZTS with Cu/Zn + Sn tilde 1.01 and Zn/Sn tilde 1.1 had the best power factor.
CERAMICS INTERNATIONAL
(2023)
Review
Nanoscience & Nanotechnology
Qing Shi, Juan Li, Xuanwei Zhao, Yiyuan Chen, Fujie Zhang, Yan Zhong, Ran Ang
Summary: This article comprehensively reviews the latest breakthroughs in high-performance (Bi, Sb)2Te3 alloys and summarizes effective strategies to further improve the thermoelectric performance from the perspectives of enhancing the power factor and minimizing the lattice thermal conductivity. Additionally, the surface states of topological insulators are investigated for advancing the (Bi, Sb)2Te3 thermoelectrics.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Physical
Angel Regalado-Contreras, M. H. Farias, W. De La Cruz
Summary: Low temperature processing and long-term electrical stability were achieved in p-type ZnO thin films by reactive pulsed laser deposition. The films exhibited stable electrical properties and emissions, even after nine months of deposition. This research provides suitable p-type ZnO:N films for flexible electronics fabrication.
APPLIED SURFACE SCIENCE
(2023)
Article
Materials Science, Ceramics
Guoqing Liang, Sichen Xu, Hao Zhou, Xiaodong Su, Run Zhao, Hao Yang, Rujun Tang
Summary: This study elucidates the dielectric relaxation properties of multiferroic hexaferrite thin films and their significant impact on magnetoelectric devices.
CERAMICS INTERNATIONAL
(2022)
Article
Physics, Multidisciplinary
Chen Zhou, Wang-Ping Cheng, Yuan-Di He, Cheng Shao, Ling Hu, Ren-Huai Wei, Jing-Gang Qin, Wen-Hai Song, Xue-Bin Zhu, Chuan-Bing Cai, Yu-Ping Sun
Summary: This study investigates the potential of Bi2Sr2CuO y and Bi2Sr1.8Nd0.2CuO y thin films as p-type transparent conductors. The results demonstrate that the Bi2Sr1.8Nd0.2CuO y thin film exhibits high transmittance and conductivity.
Article
Chemistry, Physical
Tsukasa Katayama, Shishin Mo, Akira Chikamatsu, Yuji Kurauchi, Hiroshi Kumigashira, Tetsuya Hasegawa
Summary: In this study, GdBaCo2O6 epitaxial films were successfully synthesized and reversible transformation between x = 5.5 and 6 phases was achieved via low-temperature redox reactions. The x = 6 film exhibited ferromagnetic and metallic behavior below 110 K and semiconducting behavior above. The ferromagnetic interaction between Co3.5+ and Gd3+ contributed to the magnetization and the half-metallicity of the film.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Inorganic & Nuclear
Hong Yan, Kotaro Fujii, Houria Kabbour, Akira Chikamatsu, Yu Meng, Yoshitaka Matsushita, Masatomo Yashima, Kazunari Yamaura, Yoshihiro Tsujimoto
Summary: Researchers have successfully grown a new gallium oxysulfide single crystal, La4Ga2S8O3, with disulfide pairs using a KI molten salt. The disulfide pairs dominate the valence band maximum and conduction band minimum, making La4Ga2S8O3 a direct-type semiconductor with an optical band gap of 2.45 eV. This research suggests that band gap engineering using multiple anions is a promising approach for developing novel photocatalysts with suitable band gap energies for water splitting and high photocorrosion resistance.
INORGANIC CHEMISTRY
(2023)
Article
Physics, Applied
Tsukasa Katayama, Shishin Mo, Akira Chikamatsu, Tetsuya Hasegawa
Summary: Epitaxial M-type BaFe12O19 flexible sheets with RT perpendicular magnetization were successfully synthesized on mica substrates using solid phase epitaxy method. Optimization of the synthesis process involved preparation of amorphous BaFe12O19 films on Al2O3-buffered mica substrates and annealing at high temperatures for single crystallization. The prepared sheets exhibited perpendicular ferrimagnetism with high saturated magnetization and magnetic anisotropy coefficient, along with flexibility.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Applied
Tsukasa Katayama, Kento Magara, Akira Chikamatsu, Tetsuya Hasegawa
Summary: The proton conductive properties of perovskite oxides have attracted attention for various applications. Two-dimensional proton conduction was theoretically predicted in the double-perovskite GdBaCo2O5.5 with a specific Gd/Ba order. The anisotropic proton conductivity was experimentally confirmed in GdBaCo2O5.5 epitaxial films, showing slower conductivity along the Gd/Ba order due to the hindrance from BaO planes with large Ba2+ ions.
APPLIED PHYSICS LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Akihiro Nishida, Tsukasa Katayama, Yasutaka Matsuo
Summary: In this study, HfO2 thin films were fabricated using a novel Cl-free Hf precursor, Hf(dmap)4, through ALD. The results showed that Hf(dmap)4 exhibited high stability and decomposition temperature at high temperatures, making it suitable for high-temperature ALD. However, the film growth rate was lower due to the steric hindrance of the precursor structure.
ACS APPLIED NANO MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Rui Yu, Lizhikun Gong, Hiromichi Ohta, Tsukasa Katayama
Summary: Flexible oxide sheets with ferroelectricity and high permittivity are crucial for emerging technologies. However, cracks are easily formed when reducing the thickness of oxide sheets. In this study, we successfully fabricated crack-free oxide sheets by using a protective layer and a suitable bottom electrode. These sheets exhibit excellent ferroelectric switching behavior and high permittivity.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Shishin Mo, Tsukasa Katayama, Akira Chikamatsu, Tetsuya Hasegawa
Summary: By grain engineering of Mn2Mo3O8 films, the magnetic transition temperature (T-N) can be enhanced, mainly by controlling the volume fraction of the grains. The volume fraction of G2 grains varies with the film thickness, and the T-N of the grain engineered Mn2Mo3O8 films increases accordingly.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Chemistry, Inorganic & Nuclear
Lizhikun Gong, Rui Yu, Hiromichi Ohta, Tsukasa Katayama
Summary: In this study, crack-free La-doped BaSnO3 (LBSO) epitaxial sheets were successfully synthesized using a water-soluble Sr3Al2O6 sacrificial layer and an amorphous (a-)Al2O3 protection layer via a lift-off and transfer method. The LBSO sheet exhibited high electron mobility and wide optical bandgap due to its epitaxial crystallinity, and two different shapes of sheets were prepared.
DALTON TRANSACTIONS
(2023)
Article
Engineering, Electrical & Electronic
Binjie Chen, Hiromichi Ohta, Tsukasa Katayama
Summary: In this study, the ferroelectric properties of h-ErFeO3 films were successfully investigated by improving the material preparation. The films exhibited four types of ferroic properties: antiferroelectric, ferroelectric, antiferromagnetic, and weak ferromagnetic.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Binjie Chen, Hiromichi Ohta, Tsukasa Katayama
Summary: In this study, h-ErFeO3 films with limited electric leakage current were successfully prepared, allowing the investigation of its ferroelectric properties. It was found that the h-ErFeO3 films can exhibit both antiferroelectric and ferroelectric behaviors, and an antiferromagnetic-to-weak ferromagnetic phase transition was observed as well.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Binjie Chen, Tsukasa Katayama
Summary: This study reports a method for preparing h-RFeO3 pure-phase thin films on glass substrates, with the formation of metastable phase achieved through pulsed laser deposition, allowing observation of its ferroelectricity and magnetic phase transition at room temperature.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Takahiro Maruyama, Yasushi Hirose, Tsukasa Katayama, Yuki Sugisawa, Daiichiro Sekiba, Tetsuya Hasegawa, Akira Chikamatsu
Summary: The perovskite-type europium niobium oxynitride (EuNbO2N) exhibits colossal negative magnetoresistance at low temperatures, and the negative MR ratio increases with nitrogen content. The transport properties of EuNbO3-xNx thin films change gradually from metallic to semiconducting as the nitrogen content increases, which is attributed to carrier localization caused by the random distribution of nitrogen at anion sites. The d-f exchange interaction between localized Nb 4d(1) and Eu2+ 4f electrons is speculated to be a key factor in the colossal negative MR of EuNbO3-xNx.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
