Review
Materials Science, Ceramics
Vitaly Gurylev, Tsong Pyng Perng
Summary: Defects in zinc oxide (ZnO) play a crucial role in influencing its properties and applications, with potential for improved characteristics through the introduction of oxygen and zinc vacancies. Defective ZnO shows broad application potential in nanoscale devices, yet faces challenges and requires further research for in-depth exploration.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Michael Titze, Heejun Byeon, Anthony Flores, Jacob Henshaw, C. Thomas Harris, Andrew M. Mounce, Edward S. Bielejec
Summary: This study presents an in situ counted ion implantation experiment that significantly reduces the error on the number of ions required to form a single optically active silicon vacancy (SiV) defect in diamond compared to traditional timed implantation. By analyzing the ion number using in situ detection and postimplantation analysis, the error is improved by 7-fold compared to timed implantation. Additionally, the study confirms the presence of single-photon emitters in 82% of the analyzed positions through Hanbury-Brown-Twiss interferometry.
Article
Materials Science, Multidisciplinary
Xi Zhang, Sergiy Divinski, Blazej Grabowski
Summary: In this study, ab initio density-functional-theory calculations were used to investigate the vacancy formation and migration energies in HCP Al-Hf-Sc-Ti-Zr high entropy alloys (HEAs) and their subsystems. The temperature-dependent formation Gibbs energies and averaged atomic environments were obtained using the special quasi-random structure approach and statistical analysis. It was found that the temperature-dependent vacancy formation Gibbs energy had a negative configurational entropy contribution. The local cluster expansion technique was applied to explore extended vacancy migration phase spaces.
Article
Nanoscience & Nanotechnology
Xiaoran Zheng, Sajjad S. Mofarah, Alan Cen, Claudio Cazorla, Enamul Haque, Ewing Y. Chen, Armand J. Atanacio, Madhura Manohar, Corey Vutukuri, Joel Luke Abraham, Pramod Koshy, Charles C. Sorrell
Summary: Metal oxide pseudocapacitors with low electrical and ionic conductivities can be enhanced through defect engineering and architectural design approaches. This study successfully demonstrated intercalation pseudocapacitance in CeO2-x, optimizing charge transfer, capacitance and kinetics through regulation of defect concentrations. Moreover, ion implantation and reduction processes were found to significantly increase specific capacitance and retention, while ordered oxygen vacancies enabled atomic channels for ion intercalation, enhancing both capacitance performance and electrical conductivities.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Engineering, Environmental
Yanshan Wan, Jibiao Li, Jiupai Ni, Chong Wang, Chengsheng Ni, Hong Chen
Summary: This study demonstrates that different crystal facets have significant effects on the catalytic performance in the gas-phase degradation of NO. ZnO crystals with lower flat-band energy and enhanced (0002) facet show better performance in the photoelectrochemical water-oxidation, while those with exposed (101(-)1) facet have higher affinity to NO molecules. Additionally, the oxygen vacancies play a minor role in the photocatalytic oxidation of NO.
JOURNAL OF HAZARDOUS MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Liyan Niu, Sulei Hong, MaoHua Wang
Summary: Modification with sodium borohydride increased the concentration of oxygen vacancy defects on the surface of ZnO, leading to enhanced sensitivity of the humidity sensor using the modified ZnO. This study reveals the effect of reducing agents on regulating defects in metal-oxide semiconductor materials.
JOURNAL OF ELECTRONIC MATERIALS
(2021)
Article
Physics, Multidisciplinary
Ren-Jie Liu, Jia-Jie Lin, N. Daghbouj, Jia-Liang Sun, Tian-Gui You, Peng Gao, Nie-Feng Sun, Min Liao
Summary: The evolution of defects in InP with 75 keV H+ and 115 keV He+ implantation at room temperature was investigated. It was found that He+ implantation caused wider damage distribution and higher out-of-plane strain compared to H+ implantation in InP. Furthermore, after annealing, H+ implanted InP did not exhibit blistering or exfoliation, while the He molecules formed large bubbles that created blisters at high fluence.
Article
Chemistry, Physical
Yonghui Zhang, Lishu Liu, Zhaoxiong Wang, Yingying Yang, Fei Xing
Summary: This study reports on light-assisted iodine ion migration in CuI and the effectiveness of UV irradiation on state transition in RRAM devices. Through various experiments and analyses, the characteristics of native defects in CuI materials and the radiation-induced defect evolution mechanism are revealed.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
Xudong An, Hongqiang Zhang, Te Zhu, Qianqian Wang, Peng Zhang, Yamin Song, Mingpan Wan, Tengfei Yang, Xingzhong Cao
Summary: This study investigated the behavior of hydrogen and its interaction with defects in pure titanium using positron annihilation spectroscopy. The results showed a positive correlation between the structural damage of pure titanium and the energy of hydrogen ion implantation. Increasing the implantation dose resulted in changes in the structural features of defects, shifting the damage range from the peak damage region to the near surface region.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Nanoscience & Nanotechnology
Linze Li, Jiangtao Hu, Jie Xiao, Chongmin Wang
Summary: This study reveals the aggregation behavior of vacancies in layer-structured cathodes using scanning transmission electron microscopy. Vacancies aggregate to form nanoclusters at the outer layer of the particle during initial charging, extending to the inner part when fully charged. With extended cycling, these nanoscale vacancy clusters become immobilized.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Simona Achilli, Nguyen H. Le, Guido Fratesi, Nicola Manini, Giovanni Onida, Marco Turchetti, Giorgio Ferrari, Takahiro Shinada, Takashi Tanii, Enrico Prati
Summary: Research explores quantum transport through Ge-vacancy complexes in silicon and identifies anomalous behavior compared to conventional dopants. The combination of a model based on ab initio results with single-ion implantation method offers potential for creating spatially controllable individual defects in silicon for applications in quantum information technology.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
Sushant Ghimire, Most Farida Khatun, Bhagyashree M. Sachith, Takuya Okamoto, Jeladhara Sobhanan, Ch Subrahmanyam, Vasudevanpillai Biju
Summary: In this study, bromide vacancies in CsPbBr3 perovskite nanocrystals were filled with NaBr, KBr, or CsBr at the organic-aqueous interface or in a polar solvent. These bromide salts increased the photoluminescence quantum yield and tuned the optical band gap of the nanocrystals. The vacancy-filled or halide-exchanged samples showed higher stability compared to ligand-capped samples. This strategy has potential for designing stable and water-soluble perovskite samples for various applications.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Tan Shi, Xi Qiu, Yundi Zhou, Sixin Lyu, Jing Li, Dan Sun, Qing Peng, Yong Xin, Chenyang Lu
Summary: The stability of small vacancy clusters in a high-entropy alloy Nb0.75ZrTiV0.5 with body-centered cubic structure was investigated using first-principles calculations and molecular dynamics simulations. The tightly bound configurations were found to have lower structural stability and were not energetically preferred in the studied alloy. The instability of these configurations led to vacancy-atom exchanges that favored less compact configurations. The formation energy of small vacancy clusters was much smaller than that of its constituent elements due to the large structural adjustment induced by severe local lattice distortion. The difference in local lattice distortion and elemental arrangement in the vacancy neighborhood resulted in significant site-to-site variation in vacancy cluster energy and configuration. The unconventional energetics of small vacancy clusters are expected to have a profound impact on their behavior and the defect microstructure evolution during irradiation.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Qian Li, Mengdi Zhang, Miaomiao Yuan, Wei Cheng, Bin Liao, Minju Ying
Summary: This study presents a comprehensive experimental and theoretical investigation on the effects of surface polarity on the structure and ferromagnetic properties of Co and Co-Sm co-implanted polar ZnO films. The results show that O-polar ZnO exhibits stronger ferromagnetism, possibly due to the combination of more oxygen vacancies and larger local moments related to Co and Sm doping.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Materials Science, Multidisciplinary
Can Huang, Qiufan Wang, Guofu Tian, Daohong Zhang
Summary: This study reports a novel oxygen-deficient Mn3O4 nanoframes cathode for rechargeable aqueous zinc-ion batteries with high capacity and good electrochemical stability. The cathode spheres exhibit excellent gravimetric capacity and high energy density, with ex situ X-ray diffraction and X-ray photoelectron spectroscopy showing the mechanism of insertion and extraction of H+ and Zn2+. Theoretical modeling reveals that defect engineering can significantly improve the electrochemical performance of Mn3O4 in aqueous rechargeable batteries.
MATERIALS TODAY PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Tianxiang Lin, Si-Hua Li, Lok-Ping Ho, Andrej Kuznetsov, Ho Nam Lee, Tony Chau, Francis Chi-Chung Ling
Summary: The fabrication of SiC junction barrier Schottky diodes involves Al ion implantation for p-type doping. By using a new fabrication method, it has been found that low temperature annealing followed by thermal oxidation can solve the trade-off between high Al acceptor activation and low residual concentration of carbon vacancies. This results in the suppression of carbon vacancies and a significant reduction in the reverse leakage current.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Physics, Applied
Alexander Azarov, Augustinas Galeckas, Francis Chi-Chung Ling, Andrej Kuznetsov
Summary: Ion implantation is an effective method for introducing defects into semiconductors. In this study, we investigated the use of crystallographically aligned implants to control the balance between optically active defects in ZnO. Optical data and structural analysis confirmed the formation of different dominant crystalline defects in samples implanted along and off the [0001] direction. The proportions of extended and point defects in the initial as-implanted states of these samples were found to significantly influence the defect-related luminescence upon annealing. We conclude that channeling implants have value in functionalizing defects in semiconductors by tuning specific spectral contents in defect-related emission bands.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Augustinas Galeckas, Robert Karsthof, Kingsly Gana, Angela Kok, Marianne Etzelmueller Bathen, Lasse Vines, Andrej Kuznetsov
Summary: Carrier lifetime control of 150 μm thick 4H-SiC epitaxial layers via thermal generation and annihilation of carbon vacancy (V-C) related Z(1/2) lifetime killer sites is achieved. The defect development during SiC processing steps is monitored using electrical characterization techniques and a novel all-optical approach. The lifetime control is realized by initial high-temperature treatment to increase V-C concentration followed by a moderate-temperature post-annealing. A significant increase in lifetime is observed after the post-annealing, indicating the reduction of V-C-related Z(1/2) sites.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Nanoscience & Nanotechnology
Jon Borgersen, Robert Karsthof, Vegard Ronning, Lasse Vines, Holger von Wenckstern, Marius Grundmann, Andrej Yu Kuznetsov, Klaus Magnus Johansen
Summary: Significant resistivity variations have been observed in oxides subjected to low ion doses, which cannot be explained by bulk defects. A comparative study of In2O3-based oxides revealed correlations between resistivity evolution, low ion doses, and UV illumination. The resistivity drops were attributed to oxygen desorption facilitated by irradiation/illumination, as confirmed by post-irradiation exposure to oxygen atmosphere.
Review
Physics, Applied
Filip Tuomisto
Summary: The presence of Ga vacancies and their unusual structure in beta-Ga2O3 have been extensively studied, and both experimental techniques and theoretical calculations confirm that the split Ga vacancy configuration has the lowest formation energy. However, the anisotropic signal and lack of a proper reference sample pose challenges for experiments like positron annihilation spectroscopy. Despite these challenges, the majority of data strongly indicates that high concentrations of split Ga vacancies exist in various configurations in beta-Ga2O3 samples. EPR, IR spectroscopy, and scanning transmission electron microscopy experiments all suggest that the split Ga vacancy configuration is the most likely interpretation of the data. However, the exact structure of the split Ga vacancies in terms of complexes with O vacancies and hydrogen still needs further investigation.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Applied
A. Y. Polyakov, A. I. Kochkova, A. Azarov, V. Venkatachalapathy, A. V. Miakonkikh, A. A. Vasilev, A. V. Chernykh, I. V. Shchemerov, A. A. Romanov, A. Kuznetsov, S. J. Pearton
Summary: Ion beam fabrication of metastable polymorphs of Ga2O3, assisted by the controllable accumulation of the disorder in the lattice, is explored for its alternative approach to conventional deposition techniques. In this study, two strategies - ion implantation of silicon donors and plasma treatment with hydrogen - are investigated for tuning the electron concentration in the ion beam created metastable kappa-polymorph. The results show that silicon doping did not change the high resistive state, while hydrogen plasma treatment converted the ion beam fabricated kappa-polymorph to n-type conductivity.
JOURNAL OF APPLIED PHYSICS
(2023)
Review
Materials Science, Multidisciplinary
G. Velisa, F. Granberg, E. Levo, Y. Zhou, Z. Fan, H. Bei, F. Tuomisto, K. Nordlund, F. Djurabekova, W. J. Weber, Y. Zhang
Summary: Systematic temperature-effects investigations on damage evolution in ion-irradiated Ni-based concentrated solid-solution alloys are crucial for ensuring their reliability in nuclear applications. By comparing experimental and theoretical data on equiatomic NiFe, NiCoCr, and NiCoFeCr alloys, as well as new ion channeling results on ion-irradiated NiCoFeCr at 500 K, we suggest that the lower migration energy of vacancies in NiCoCr is the reason why it is no longer outperforming NiFe under ion irradiation above 300 K, as supported by independent theoretical calculations and TEM results from the literature.
JOURNAL OF MATERIALS RESEARCH
(2023)
Article
Engineering, Electrical & Electronic
Marta Sawicka, Oliwia Golyga, Natalia Fiuczek, Grzegorz Muziol, Anna Feduniewicz- Zmuda, Marcin Siekacz, Henryk Turski, Robert Czernecki, Ewa Grzanka, Igor Prozheev, Filip Tuomisto, Czeslaw Skierbiszewski
Summary: A method for fabricating buried hollow channels inside GaN structures using selective area doping and electrochemical etching is presented. The channel width is defined by selective area ion implantation mask geometry and the vertical dimension depends on implantation energy and annealing conditions. The proposed technology has potential for integration with device fabrication and processing, as observed by X-ray diffraction for strain removal and surface roughness evaluation.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2023)
Editorial Material
Materials Science, Multidisciplinary
Andrej Kuznetsov, Wisanu Pecharapa
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Physics, Condensed Matter
Igor Prozheev, Malgorzata Iwinska, Tomasz Sochacki, Michal Bockowski, Rene Bes, Filip Tuomisto
Summary: The results of positron lifetime and X-ray absorption spectroscopy in Si-doped GaN crystals, grown by HVPE, are presented. High Si concentration leads to significant compensation effects. Ga vacancies are insufficient as compensation centers and other acceptor-like impurities are present at much lower concentrations than Si. X-ray absorption shows that the local environment of Si dopants is different in compensated samples. Simulated spectra suggest that Si has a higher presence in the nearest local environment in compensated spectra, indicating autocompensation of Si dopants in high Si content GaN samples grown by HVPE.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2023)
Article
Nuclear Science & Technology
T. Vuoriheimo, A. Liski, P. Jalkanen, T. Ahlgren, K. Mizohata, K. Heinola, Y. Zayachuk, K. K. Tseng, C. W. Tsai, J. W. Yeh, F. Tuomisto
Summary: Plasma-facing components in future fusion reactors require high temperature and particle resilience. Tungsten is currently the primary material due to its properties, but better alternatives are being explored. This study investigates the effects of hydrogen isotope exchange in an equiatomic high entropy alloy (HEA), providing insight into its suitability for fusion applications.
NUCLEAR MATERIALS AND ENERGY
(2023)
Article
Chemistry, Physical
P. Jaroszynski, E. Grzanka, M. Grabowski, G. Staszczak, I. Prozheev, R. Jakiela, F. Tuomisto, M. Bockowski
Summary: This study investigated the europium doping of gallium nitride using a novel ultra-high pressure annealing method. Ammonothermal gallium nitride substrates (n-type) were used as targets for europium ion implantation. The implanted samples were annealed at high nitrogen pressure and temperatures ranging from 1473 K to 1753 K. The concentration profiles of europium and the morphology and structural quality of the samples were analyzed. The presence of optically active EuGa-X defect complexes was suggested based on photoluminescence spectra analysis at low temperature (20 K). The limitations of diffusion-based europium doping of ammonothermal gallium nitride are discussed.
APPLIED SURFACE SCIENCE
(2023)
Article
Multidisciplinary Sciences
Rui Zhu, Huili Liang, Shangfeng Liu, Ye Yuan, Xinqiang Wang, Francis Chi-Chung Ling, Andrej Kuznetsov, Guangyu Zhang, Zengxia Mei
Summary: In this study, a new optoelectronic memory based on a photosensitive dielectric (PSD) architecture was proposed. Data writing and erasing were achieved by optical pulse, reducing the programming voltage and optical power density. This discovery provides a brand new direction for low energy consumption non-volatile optoelectronic memories.
NATURE COMMUNICATIONS
(2023)
Article
Environmental Sciences
Samriti, Marina Rumyantseva, Shuhui Sun, Andrej Kuznetsov, Jai Prakash
Summary: This paper discusses the research on the detection and removal of air pollutants using novel multifunctional nanomaterials. These emerging nano materials have high stability, sensitivity down to parts per-billion level, and excellent removal efficiency for air pollutants. The focus is on their specific strategies and recent highlights in environmental and health monitoring. The challenges and future prospects are also discussed.
CURRENT OPINION IN ENVIRONMENTAL SCIENCE & HEALTH
(2023)
Article
Materials Science, Multidisciplinary
K. A. Simula, J. Haerkonen, I. Zhelezova, N. D. Drummond, F. Tuomisto, I. Makkonen
Summary: The paper presents a variational quantum Monte Carlo method for simulating the momentum densities of annihilating electron-positron pairs in semiconductors and insulators. By comparing experimental data with simulation results, it is demonstrated that direct modeling of electron-positron correlations is important for supporting the theory of positron annihilation spectroscopies.
