Article
Chemistry, Physical
Marek Wisniewski, Joanna Czarnecka, Paulina Bolibok, Michal Swidzinski, Katarzyna Roszek
Summary: This study focuses on the stable fluorescent properties of biocompatible nitrogen-containing carbon quantum dots and the mechanism of fluorescence quenching in cells, demonstrating experimentally that reduced NADH acts as a quencher within cells and elucidating the process of functional group transformation on carbon quantum dots' surface due to redox reactions. Understanding these mechanisms will aid in accurately dosing and quantifying the internalized carbon quantum dots for biomedical applications.
Article
Nanoscience & Nanotechnology
Abhiroop Chellu, Eero Koivusalo, Marianna Raappana, Sanna Ranta, Ville Polojarvi, Antti Tukiainen, Kimmo Lahtonen, Jesse Saari, Mika Valden, Heli Seppanen, Harri Lipsanen, Mircea Guina, Teemu Hakkarainen
Summary: Several passivation techniques for close-to-surface InAs/GaAs quantum dots were compared for their ability to preserve optical properties. It was found that AlNx passivation method significantly reduces surface recombination velocity and shows long-term stability.
Article
Materials Science, Multidisciplinary
Bin-Bin Zhang, Jia-Kai Chen, Cong Zhang, Naoto Shirahata, Hong-Tao Sun
Summary: Using a combination of spectroscopic techniques, we investigated the precursor chemistry of tin-based perovskite nanocrystals. We found that active intermediate complexes formed through the reaction of the iodide source with oligomers present in the tin(II) carboxylates play a key role in governing the reactivity of the tin iodide precursor, affecting the size, size uniformity, and photoluminescence quantum yield of the nanocrystals. Understanding the precursor chemistry is crucial for the design and synthesis of tin halide perovskite nanocrystals.
ACS MATERIALS LETTERS
(2023)
Article
Computer Science, Information Systems
Sergey Balakirev, Natalia Chernenko, Natalia Kryzhanovskaya, Nikita Shandyba, Danil Kirichenko, Anna Dragunova, Sergey Komarov, Alexey Zhukov, Maxim Solodovnik
Summary: We studied the influence of arsenic pressure on the low-temperature GaAs overgrowth of InAs quantum dots and their optical properties. High arsenic pressure led to a unimodal size distribution of quantum dots and lower photoluminescence intensity. Low arsenic pressure resulted in the formation of arrays of quantum dots with larger sizes.
Article
Crystallography
Sergey Balakirev, Danil Kirichenko, Natalia Chernenko, Nikita Shandyba, Sergey Komarov, Anna Dragunova, Natalia Kryzhanovskaya, Alexey Zhukov, Maxim Solodovnik
Summary: In this study, we demonstrate the significant influence of arsenic pressure used for high-rate GaAs capping on the optical properties of self-assembled InAs quantum dots. An increase in overgrowth arsenic pressure leads to a red shift in the photoluminescence peak position, which can be explained by the different intensities of quantum dot decomposition. High arsenic pressure results in a GaAs capping layer that has a low impact on the initial quantum dots, while low arsenic pressure leads to intensive intermixing. This study provides evidence for the strong effect of overgrowth arsenic pressure on the characteristics of InAs quantum dots.
Article
Materials Science, Multidisciplinary
Huizi Tang-Wang, Chuan Zhou, Ying Wang, Yingnan Guo, Shufang Wang, Guangsheng Fu, Baolai Liang, Yuriy I. Mazur, Morgan E. Ware, Gregory J. Salamo
Summary: In this study, InAs(Sb)/GaAs self-assembled quantum dots (QDs) with type II band alignment were successfully grown by incorporating Sb into InAs and increasing the beam equivalent pressure ratio. These InAsSb QDs exhibit different characteristics compared to the well-studied type-I InAs QDs in terms of excitation intensity, temperature dependence, and luminescence time dependence. The Sb distribution in the QDs and the wetting layer was also investigated.
Article
Physics, Multidisciplinary
Petr Steindl, Elisa Maddalena Sala, Benito Alen, Dieter Bimberg, Petr Klenovsky
Summary: Studied the optical properties and carrier dynamics of (InGa)(AsSb)/GaAs/GaP quantum dots, revealing common spectral features and observations of emission from the QDs with recombination times between 2 ns and 10 ns. Suggested potential applications of these QDs in nano memory devices and quantum photonic sources due to their considerable tunability and nearly defect-free growth capabilities on Si. Analysis confirmed the nature of emission blue-shift due to charged-background induced changes of wavefunction spatial distribution.
NEW JOURNAL OF PHYSICS
(2021)
Review
Chemistry, Multidisciplinary
Xinzhe Xiao, Yumin Zhang, Lei Zhou, Bin Li, Lin Gu
Summary: Graphene oxide (GO) is an excellent photoluminescence (PL) material with unique optical properties. It has been widely used in various fields such as material science and biomedicine. The luminescence mechanism of GO and GOQDs is still not fully understood, but they show potential in medical imaging and biosensors.
Article
Chemistry, Physical
N. Ruiz-Marin, D. F. Reyes, L. Stanojevic, T. Ben, V. Braza, A. Gallego-Carro, G. Barcena-Gonzalez, J. M. Ulloa, D. Gonzalez
Summary: Recently, very thin AlAs capping layers have been proposed as a useful tool to enhance the performance of InAs/GaAs quantum dot devices. The height and In content of InAs QDs increase progressively with the AlAs capping layer thickness, showing a strong shielding effect against QD decomposition. For AlAs capping layers above 5 ML thickness, QD populations split into a bimodal distribution of smaller lenticular QDs and larger truncated pyramids.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Analytical
Xue Gong, Qingqing Cai, Jiajia Zhang, Yuanhong Min, Wensheng Fu, Yi Wang, Pu Zhang
Summary: Inorganic pyrophosphate anions (PPi) play a crucial role in biological processes and serve as important indicators for physiological function evaluation and disease diagnosis. However, there is a lack of straightforward and robust approaches for PPi detection. In this study, an on-off-on fluorescent switching nanoprobe utilizing Fe3+-mediated fluorescent sulfur quantum dots (SQDs) is designed for highly robust PPi detection. The SQDs, capped with bovine serum protein (BSA), exhibit good water dispersibility and optical stability. The presence of Fe3+ induces aggregation of the SQDs, leading to fluorescence quenching. PPi selectively binds with Fe3+, preventing SQD aggregation and resulting in fluorescence recovery. The designed nanoswitch shows great potential for the future development of quantum dot-based biosensors for analyte detection.
Article
Chemistry, Physical
Pawel Holewa, Jakub Jasinski, Artem Shikin, Elizaveta Lebedkina, Aleksander Marynski, Marcin Syperek, Elizaveta Semenova
Summary: The research on InAs/InP quantum dots (QDs) using time-integrated (PL) and time-resolved photoluminescence (TRPL) experiments reveals carrier confinement and losses among QDs, as well as different emission modes due to size distribution. TRPL experiment highlights the role of carrier reservoir in QDs capture process and the influence of different confinement regimes on PL decay time.
Article
Chemistry, Multidisciplinary
Yangyang Ju, Xian-gang Wu, Sheng Huang, Guang Dai, Tinglu Song, Haizheng Zhong
Summary: The time evolution of photoluminescence properties in phenylethylammonium tin halide perovskite (PEA(2)SnI(4)) film has been reported as a function of oxygen concentration. Oxygen concentration significantly affects the photoluminescence emission of the PEA(2)SnI(4) film, with low oxygen concentration leading to photo-brightening and high oxygen concentrations causing irreversible photoluminescence quenching.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Chemistry, Inorganic & Nuclear
Yi-Lei Xu, Yayun Ding, Lin-Mei Zhang, Hao Ma, Jia-Xing Liu, Jiaxu Zhang, Rui Zhou, Dong-Sheng Li, Shang-Fu Yuan, Tao Wu
Summary: In this study, the influence of distinct chemical components on defect position in copper-containing I-III-VI nanoclusters was explored. It was found that the presence of trivalent metal ions significantly affects the trap sites, and fine-tuning of luminescence properties can be achieved by introducing Cd ions.
INORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Nanoscience & Nanotechnology
H. Mohammadi, R. C. Roca, I Kamiya
Summary: Strain control and photoluminescence enhancement of InAs surface quantum dots have been achieved by introducing buried quantum dots. The study shows that strain and related effects dominate the electronic properties of the quantum dots, and buried quantum dots act as effective carrier reservoirs.
Article
Nanoscience & Nanotechnology
Robert Sittig, Cornelius Nawrath, Sascha Kolatschek, Stephanie Bauer, Richard Schaber, Jiasheng Huang, Ponraj Vijayan, Pascal Pruy, Simone Luca Portalupi, Michael Jetter, Peter Michler
Summary: In this study, a novel InGaAs metamorphic buffer is developed using metal-organic vapor-phase epitaxy (MOVPE) with a nonlinear indium content grading profile. The thin-film buffer allows for the necessary transition of the lattice constant and provides a smooth surface for the growth of InAs quantum dots, resulting in single-photon emission at 1550 nm. The successful integration of this new design into a photonic resonator demonstrates its potential for high-quality nonclassical light sources in telecommunication.
Article
Chemistry, Physical
M. Stachowicz, A. Wierzbicka, J. M. Sajkowski, M. A. Pietrzyk, P. Dluzewski, E. Dynowska, J. Dyczewski, K. Morawiec, S. B. Kryvyi, S. Magalhaes, E. Alves, A. Kozanecki
Summary: This study analyzed heteroepitaxially grown ZnO/MgO superlattices on a-oriented ZnO substrates. It found that the different crystalline structures of ZnO and MgO influence the abruptness of the interface and the retention of the wurtzite structure. The wurtzite structure can be retained in the MgO thin barriers, but it inevitably leads to non-uniform biaxial strains and interdiffusion of Mg from barriers to ZnO QW's. The complex strain/composition heterogeneities can be explained by the difference in vapor pressure between Mg and Zn elements and the high mobility of Mg atoms. A ZnMgO film of three monolayers size was created at the interfaces, which partly contributes to retaining the wurtzite structure of the coherently grown MgO layers.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Joao R. Martins, Victor Krivenkov, Cesar R. . Bernardo, Pavel Samokhvalov, Igor Nabiev, Yury P. Rakovich, Mikhail I. Vasilevskiy
Summary: In this study, a method for analyzing the photoluminescence decay curves of fluorophores is presented using the statistical moments. The proposed method shows high efficiency and accuracy in analyzing the decay kinetics of CdSe quantum dots and QD systems, and it can identify the most appropriate theoretical decay function for describing the systems under study.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Andrei V. Turutin, Elena A. Skryleva, Ilya V. Kubasov, Filipp O. Milovich, Alexander A. Temirov, Kirill V. Raketov, Aleksandr M. Kislyuk, Roman N. Zhukov, Boris R. Senatulin, Victor V. Kuts, Mikhail D. Malinkovich, Yuriy N. Parkhomenko, Nikolai A. Sobolev
Summary: In this article, a new technology of non-contact mapping of magnetic fields produced by the human heart muscle using miniaturized and highly sensitive magnetic field sensors is described. The technology involves the use of laminated magnetoelectric heterostructures comprising a thin piezoelectric lithium niobate single crystal and a film of magnetostrictive metglas. High quality metglas layers were deposited by magnetron sputtering and their performance was evaluated. The developed sensors achieved a high magnetoelectric coefficient, a low noise level, and an improved detection limit for AC magnetic fields.
Article
Chemistry, Multidisciplinary
Rui Dias, Jose C. Viana Gomes, Mikhail I. Vasilevskiy
Summary: The generation of graphene surface plasmons (SPs) through a frequency-difference nonlinear process caused by the interaction of two optical beams was experimentally confirmed. However, the observed differential reflectance requires larger second-order optical conductivities than currently calculated.
APPLIED SCIENCES-BASEL
(2022)
Article
Physics, Applied
A. Azouaoui, A. Harbi, M. Moutaabbid, N. Benzakour, A. Hourmatallah, K. Bouslykhane, R. Masrour, A. Chahboun
Summary: Using density functional theory (DFT), the properties of NaCaZ (Z=N, P, As) half-Heusler (HH) semiconductor materials under pressure were studied. The results show that NaCaZ is chemically stable in the a-phase structure and exhibits semiconducting behavior with an indirect bandgap. Optical parameters such as complex dielectric function, absorption coefficient, and refractive index were investigated, revealing low reflectivity and high absorption coefficient in the low ultraviolet and visible regions. The materials were found to be mechanically and dynamically stable, making them promising for applications in solar cells, optoelectronics, and 2D devices.
INTERNATIONAL JOURNAL OF MODERN PHYSICS B
(2023)
Article
Physics, Applied
S. Magalhaes, J. S. Cabaco, O. Concepcion, D. Buca, M. Stachowicz, F. Oliveira, M. F. Cerqueira, K. Lorenz, E. Alves
Summary: The study demonstrates the importance of accurately determining the strain states of semiconductor compounds and introduces a new software called LAPAs. The lattice parameters and chemical composition of Al1-xInxN and Ge1-xSnx compounds grown on different substrates are calculated using the Bond's method and compared with results from x-ray diffraction. The findings show that broad peaks contribute significantly to the uncertainty in lattice parameters, and the inclusion of refraction correction has a small impact on the results. The differences between real space and reciprocal space methods are also discussed.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
A. T. Costa, Mikhail I. Vasilevskiy, J. Fernandez-Rossier, Nuno M. R. Peres
Summary: This article investigates the challenges of forming hybrid plasmon-magnon polaritons in heterostructures and demonstrates the possibility of polaritons formed by graphene plasmons and magnons in two-dimensional ferromagnetic insulators.
Article
Physics, Multidisciplinary
C. M. Vitor, E. Alves, R. C. da Silva, R. Mateus, J. Cruz, N. Catarino
Summary: In this study, ion beam analysis techniques were used to investigate the Be-related plasma-wall interactions. New data sets for the differential cross sections Be-9(He-3,p( i ))B-11 were obtained, and the results were found to be consistent with previous studies. A benchmarking measurement was performed to validate the results.
Editorial Material
Materials Science, Multidisciplinary
Nikolai A. Sobolev
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Eliana M. F. Vieira, Jose P. B. Silva, Katarzyna Gwozdz, Adrian Kaim, Nuno M. Gomes, Adil Chahboun, Maria J. M. Gomes, Jose H. Correia
Summary: This research shows that introducing a thin SnO film between the Si substrate and the ZnO film can result in a stable and high-performing self-powered photodetector. The SnO layer enhances the photocurrent by over 1000% by introducing a built-in electrostatic field. The underlying physical mechanism of the self-powered violet photodetectors is explained through energy diagrams of the p-n junction. The Si/SnO/ZnO/ITO device exhibits a significant enhancement in responsivity compared to the Al/Si/ZnO/ITO, with a fast response time of approximately 2 μs.
Article
Chemistry, Physical
Mindaugas Andrulevicius, Evgenii Artiukh, Gunnar Suchaneck, Sitao Wang, Nikolai A. A. Sobolev, Gerald Gerlach, Asta Tamuleviciene, Brigita Abakeviciene, Sigitas Tamulevicius
Summary: X-ray photoelectron spectroscopy was used to investigate the direct synthesis of strontium and molybdenum oxide thin films by multitarget reactive magnetron sputtering. By varying the power applied to the Mo target, films with different concentrations of Mo atoms were produced. The XPS spectra revealed that both molybdenum and strontium were in the oxidized state, with Mo bonds in a lower valence state and similar Sr spectra for all samples.
Article
Nuclear Science & Technology
Y. Zayachuk, N. Catarino, C. Smith, I. Jepu, C. Ayres, A. Widdowson, E. Alves, M. Rubel, JET Contributors
Summary: In this study, beryllium samples with co-deposits or surface cracks caused by melt damage were immersed into boiling water to simulate the impact of coolant water ingress into a tokamak. The results showed that there was no thermomechanical damage to the samples during exposure, and no measurable release of deuterium occurred. Only some degree of surface oxidation was observed, but no thick oxide films were formed.
NUCLEAR MATERIALS AND ENERGY
(2023)
Article
Biochemistry & Molecular Biology
Nenad Bundaleski, Carolina F. Adame, Eduardo Alves, Nuno P. Barradas, Maria F. Cerqueira, Jonas Deuermeier, Yorick Delaup, Ana M. Ferraria, Isabel M. M. Ferreira, Holger Neupert, Marcel Himmerlich, Ana Maria M. B. do Rego, Martino Rimoldi, Orlando M. N. D. Teodoro, Mikhail Vasilevskiy, Pedro Costa Pinto
Summary: There has been growing interest in using amorphous carbon thin films with low secondary electron yield (SEY) to reduce electron multipacting in particle accelerators and RF devices. Previous studies have shown that the SEY increases with the amount of hydrogen and is correlated with the Tauc gap. In this study, films produced by magnetron sputtering with varying amounts of hydrogen and deuterium were analyzed, and it was found that the maximal SEY decreases with the fraction of the graphitic phase in the films.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Materials Science, Coatings & Films
C. F. Adame, E. Alves, N. P. Barradas, P. Costa Pinto, Y. Delaup, I. M. M. Ferreira, H. Neupert, M. Himmerlich, S. Pfeiffer, M. Rimoldi, M. Taborelli, O. M. N. D. Teodoro, N. Bundaleski
Summary: In this study, a systematic characterization of deuterium-contaminated a-C coatings was performed to establish a correlation between hydrogen content and secondary electron emission properties. The results showed that hydrogen impurities increase the secondary electron yield (SEY) of a-C films. Mechanisms of contamination were also investigated, revealing a process involving target poisoning and physical sputtering. The maximum SEY (SEYmax) increased linearly with relative D/H amounts between 11% and 47%, and abruptly increased in the range of 47%-54% when the nature of the deposited films changed.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Physics, Multidisciplinary
E. P. Alves, F. Fiuza
Summary: This study reports the data-driven discovery of accurate reduced plasma models directly from first-principles particle-in-cell simulations, demonstrating the potential of this approach to accelerate the development of reduced theoretical models of complex nonlinear plasma phenomena and design computationally efficient algorithms for multiscale plasma simulations.
PHYSICAL REVIEW RESEARCH
(2022)
