Article
Chemistry, Physical
Chenjia Mi, Matthew L. Atteberry, Varun Mapara, Lamia Hidayatova, Gavin C. Gee, Madalina Furis, Wai Tak Yip, Binbin Weng, Yitong Dong
Summary: This study demonstrates that CsPbBr3 perovskite quantum dots (QDs) embedded in a phenethylammonium bromide matrix show a well-passivated surface and improved photostability under intense photoexcitation. Photoluminescence blinking is suppressed and a spectral blue-shift is observed in the SCPQDs at moderate excitation intensities, which is attributed to a biexciton-like Auger interaction between excitons and trapped excitons formed by surface lattice elastic distortions. The unique repulsive biexciton interaction observed in the SCPQDs supports this hypothesis.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Physics, Applied
Georgios Nousios, Thomas Christopoulos, Odysseas Tsilipakos, Emmanouil E. Kriezis
Summary: In this study, we assess the performance of a photonic laser cavity composed of a silicon-rich-nitride-on-insulator disk resonator overlaid with a transition-metal dichalcogenide (TMD) bilayer heterostructure. By using a rigorous theoretical framework based on perturbation theory and temporal coupled-mode theory, we propose a silicon-on-insulator-compatible optical source capable of emitting milliwatt power inside an integrated waveguide.
PHYSICAL REVIEW APPLIED
(2023)
Article
Chemistry, Multidisciplinary
Y. Galvao Gobato, C. Serati de Brito, A. Chaves, M. A. Prosnikov, T. Wozniak, Shi Guo, Ingrid D. Barcelos, M. V. Milosevic, F. Withers, P. C. M. Christianen
Summary: We investigated the valley Zeeman splitting of excitonic peaks in high-quality hBN/WS2/MoSe2/hBN heterostructures under perpendicular magnetic fields. The lower-energy peak exhibits a smaller g-factor compared to other vdW heterostructures. Evidence suggests that this discernible difference is due to excitonic confinement in the potential landscape created by the moire pattern in heterobilayers.
Article
Chemistry, Multidisciplinary
Simon C. Boehme, Maryna I. Bodnarchuk, Max Burian, Federica Bertolotti, Ihor Cherniukh, Caterina Bernasconi, Chenglian Zhu, Rolf Erni, Heinz Amenitsch, Denys Naumenko, Hordii Andrusiv, Nazar Semkiv, Rohit Abraham John, Alan Baldwin, Krzysztof Galkowski, Norberto Masciocchi, Samuel D. Stranks, Gabriele Raino, Antonietta Guagliardi, Maksym V. Kovalenko
Summary: The success of colloidal semiconductor quantum dots (QDs) is due to the precise control of QD size, shape, and composition, which has enabled the development of well-defined functional nanomaterials. Although the strong confinement regime has been extensively explored for InP or CdSe QDs, it has not been thoroughly investigated for lead-halide perovskite QDs. This is mainly due to the limited chemical stability and size monodispersity of perovskite QDs smaller than 7 nm.
Article
Chemistry, Multidisciplinary
Wenqi Qian, Pengfei Qi, Yuchen Dai, Beibei Shi, Guangyi Tao, Haiyi Liu, Xubin Zhang, Dong Xiang, Zheyu Fang, Weiwei Liu
Summary: Artificially molding exciton flux is crucial for developing promising excitonic devices. The use of hetero/homobilayers allows for spatially separated charges, prolonging the lifetime of excitons and facilitating electrical control on a large scale. Additionally, nanoscale periodic moire potentials arising from twist-angle or lattice mismatch can greatly impact exciton dynamics. However, the dynamics of spatially indirect excitons in homobilayers without lattice mismatch remain unknown. In this study, the nonequilibrium dynamics of indirect excitons in homobilayers are investigated, revealing the strong localization of moire excitons and providing insights for designing excitonic devices operating at room temperature.
Article
Engineering, Electrical & Electronic
Chongyun Jiang, Abdullah Rasmita, Hui Ma, Qinghai Tan, Zhaowei Zhang, Zumeng Huang, Shen Lai, Naizhou Wang, Sheng Liu, Xue Liu, Ting Yu, Qihua Xiong, Wei-bo Gao
Summary: A room temperature valley Hall effect can be observed in a molybdenum disulfide/tungsten diselenide van der Waals heterostructure, with electrically tunable magnitude and polarity, allowing for the creation of a bipolar valleytronic transistor.
NATURE ELECTRONICS
(2022)
Article
Chemistry, Physical
Daniel D. Kohler, Darien J. Morrow, Yuzhou Zhao, Jason M. Scheeler, Song Jin, John C. Wright
Summary: Lateral heterostructures of 2D transition metal dichalcogenides offer potential applications in various fields. This study characterizes monolayer core-shell WS2-MoS2 lateral heterostructures using photoluminescence, Raman, reflection contrast, and second harmonic generation. Comparisons with similar heterostructures created by different methods are made to understand the electronic and spatial structures.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Sudipta Kundu, Tomer Amit, H. R. Krishnamurthy, Manish Jain, Sivan Refaely-Abramson
Summary: In this study, many-body perturbation theory is used to evaluate the relationship between twist angle and exciton properties in transition metal dichalcogenide (TMD) heterostructures. An approach for unfolding excitonic states from the moire Brillouin zone onto the separate-layer ones is presented. Applying this method to a large-angle twisted MoS2/MoSe2 bilayer, it is found that the optical spectrum is dominated by mixed electron-hole transitions with different momenta in the separate monolayers, leading to unexpected hybridization between interlayer and intralayer excitons.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Chemistry, Physical
Sandhyarani Sahoo, Mousam Charan Sahu, Sameer Kumar Mallik, Neha Kapila Sharma, Anjan Kumar Jena, Sanjeev K. Gupta, Rajeev Ahuja, Satyaprakash Sahoo
Summary: In this study, we investigated the vertical electric-field-controlled interlayer charge transfer in stacked MoX2/WX2 (X=S, Se) heterostructures using density functional theory. The electric field was found to modulate band alignment, band inversion, and charge localization/delocalization in these structures, providing insight into charge transfer mechanisms. The findings suggest that interlayer charge transfer can be modulated by vertical electric fields, which has important implications for tuning electron-hole recombination and charge-transfer time in optoelectronic devices.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Astronomy & Astrophysics
Tobias Geron, Rebecca J. Smethurst, Chris Lintott, Sandor Kruk, Karen L. Masters, Brooke Simmons, Kameswara Bharadwaj Mantha, Mike Walmsley, L. Garma-Oehmichen, Niv Drory, Richard R. Lane
Summary: We studied the bar pattern speeds and corotation radii of 225 barred galaxies using MaNGA and the Tremaine-Weinberg method. We found that strongly barred galaxies have lower pattern speeds than weakly barred galaxies, suggesting that strong bars are more evolved. Interestingly, the corotation radius is not different between weakly and strongly barred galaxies, despite being proportional to bar length. Our results also show that the corotation radius differs significantly between quenching and star-forming galaxies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Physics, Applied
Huimin Zhu, Wei Zhang, Chao Ye, Jiaqi Shi, Wenxi Lu
Summary: In this study, the friction coefficient of water on graphene/h-BN heterostructures was investigated using molecular dynamics simulations. The results showed a non-monotonic but symmetrical variation with relative interlayer angle. The graphene/h-BN heterostructure is a device with different friction coefficients on both sides and can be adjusted by twisting the relative interlayer angle.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Physical
Jiting Tian, Walter Kob, Jean-Louis Barrat
Summary: Quasi-2D colloidal suspensions in a slit geometry exhibit faster diffusion and relaxation compared to their 2D counterparts due to the additional vertical space that allows overlapping of particles in the projected trajectories. The difference in dynamics can be explained by characterizing the systems using a suitable structural quantity instead of surface density. These results have practical implications for 2D colloidal experiments and provide insights into the 3D-to-2D crossover in glass-forming systems.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Calin-Andrei Pantis-Simut, Amanda Teodora Preda, Nicolae Filipoiu, Alaa Allosh, George Alexandru Nemnes
Summary: This study investigates the influence of substrates on electric-field control in phosphorene nanoribbons, finding that hexagonal boron nitride supporting layer enhances gap modulation significantly. Contacting PNRs is addressed by embedding conducting graphene nanoribbons in the support hBN layer, leading to measurable spin polarization.
Article
Physics, Applied
Ming Xin, Wenze Lan, Qinghu Bai, Xin Huang, Kenji Watanabe, Takashi Taniguchi, Gang Wang, Changzhi Gu, Baoli Liu
Summary: In this Letter, the experimental observation of trilayer exciton emission in WSe2/WS2/MoS2 heterostructures is presented. It is found that the trilayer exciton has a lower binding energy and longer lifetime compared to the bilayer exciton.
APPLIED PHYSICS LETTERS
(2022)
Article
Mathematics, Interdisciplinary Applications
J. Orosco, W. Connacher, J. Friend
Summary: This study utilizes high-speed digital holographic microscopy to observe capillary wave turbulence in a microfluidic system, discovering three types of wave turbulence and proposing a non-dimensional parameter for classification. Strongly nonlinear wave turbulence is observed at high input powers, which has important applications in areas such as microdroplets and drug research.
CHAOS SOLITONS & FRACTALS
(2023)
Article
Optics
K. Pieniak, M. Chlipala, H. Turski, W. Trzeciakowski, G. Muziol, G. Staszczak, A. Kafar, I Makarowa, E. Grzanka, S. Grzanka, C. Skierbiszewski, T. Suski
Summary: This study investigates the impact of injected current on the screening of the built-in electric field in LEDs, revealing that in LEDs with narrow quantum wells, a large portion of built-in field remains even at high injection currents, while in LEDs with wide quantum wells, the electric field is fully screened even at the lowest currents.
Article
Optics
A. Kafar, A. Sakaki, R. Ishii, S. Stanczyk, K. Gibasiewicz, Y. Matsuda, D. Schiavon, S. Grzanka, T. Suski, P. Perlin, M. Funato, Y. Kawakami
Summary: The study demonstrates the modification of epitaxial laser-like or superluminescent diode-like structures by intentional changes in substrate misorientation, affecting the indium content in the quantum well and photoluminescence emission wavelength. Simulation results show that good light guiding properties should be preserved within the studied misorientation range.
PHOTONICS RESEARCH
(2021)
Article
Physics, Applied
M. Hrytsaienko, M. Gallart, M. Ziegler, O. Cregut, S. Tamariz, R. Butte, N. Grandjean, B. Hoenerlage, P. Gilliot
Summary: This work investigates the photoluminescence properties of c-plane GaN/AlN quantum dot ensembles, revealing the existence of a relaxation channel competing with radiative recombination, and finding that the nonradiative transfer process is independent of the dot height, while the radiative recombination process depends on the emission energy characteristics.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Physical
Jacek Piechota, Stanislaw Krukowski, Petro Sadovyi, Bohdan Sadovyi, Sylwester Porowski, Izabella Grzegory
Summary: The study investigated the dissolution of molecular nitrogen in liquid gallium and iron through ab initio calculations and experiments, revealing fundamental differences in N bonding between the two solvents. It was found that the nitrogen solubility in iron is much higher than in gallium, indicating that liquid iron may be a prospective solvent for gallium nitride crystallization from metallic solutions.
Article
Physics, Applied
Yao Chen, Camille Haller, Wei Liu, Sergey Yu Karpov, Jean-Francois Carlin, Nicolas Grandjean
Summary: This study investigates the impact of GaN-buffer growth temperature on the efficiency of InGaN/GaN quantum wells, revealing that high-temperature growth promotes the creation of surface defects leading to a collapse in internal quantum efficiency. Theoretical analysis suggests that these defects are likely to be nitrogen vacancies. Furthermore, the study shows that surface defects are mainly generated at the early stage of GaN growth and reach a steady state concentration determined by the growth temperature.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Physical
Ashfaq Ahmad, Pawel Strak, Kamil Koronski, Pawel Kempisty, Konrad Sakowski, Jacek Piechota, Izabella Grzegory, Aleksandra Wierzbicka, Serhii Kryvyi, Eva Monroy, Agata Kaminska, Stanislaw Krukowski
Summary: This study uses ab initio calculations to determine the polarization difference in III-nitride compounds, showing varying polarization differences between different nitrides. In multi-quantum wells, electric fields are generated by well-barrier polarization difference, and the theoretical results are in good agreement with experimental measurements.
Article
Chemistry, Physical
Pawel Strak, Konrad Sakowski, Jacek Piechota, Ashfaq Ahmad, Izabella Grzegory, Yoshihiro Kangawa, Stanislaw Krukowski
Summary: The adsorption of atomic and molecular nitrogen on the AlN(000-1) surface was investigated using ab initio calculations and thermodynamic analysis. Different adsorption behaviors and energy changes of nitrogen were observed at various aluminum coverage levels, providing insights into the mechanisms of nitrogen adsorption on the AlN surface.
Review
Optics
Johann Stachurski, Sebastian Tamariz, Gordon Callsen, Raphael Butte, Nicolas Grandjean
Summary: This study reports on the emission properties evolution of GaN/AlN quantum dots (QDs) at different temperatures. By studying the photoluminescence of a single QD, the optimum single photon purity was measured. Temperature dependent time-resolved photoluminescence measurements on a QD ensemble revealed the complexity and temperature insensitivity of exciton recombination dynamics in this nanostructure.
LIGHT-SCIENCE & APPLICATIONS
(2022)
Article
Optics
Anat Siddharth, Thomas Wunderer, Grigory Lihachev, Andrey S. Voloshin, Camille Haller, Rui Ning Wang, Mark Teepe, Zhihong Yang, Junqiu Liu, Johann Riemensberger, Nicolas Grandjean, Noble Johnson, Tobias J. Kippenberg
Summary: Low phase noise lasers based on III-V semiconductors and silicon photonics have been widely used in the near-infrared spectral regime. Recent advancements in low-loss silicon nitride-based photonic integrated resonators have surpassed external diode and fiber lasers in terms of phase noise and frequency agility in the 1550 nm-telecommunication window. In this study, we demonstrate a hybrid integrated laser composed of a gallium nitride-based laser diode and a silicon nitride photonic chip-based microresonator operating at ultra-low wavelengths down to 410 nm in the near-ultraviolet wavelength region, which is suitable for atomic transitions addressing in applications such as atomic clocks, quantum computing, or underwater LiDAR. By self-injection locking of the Fabry-Perot diode laser to a high-Q photonic integrated microresonator, we achieve more than 100x reduction in optical phase noise at 461 nm, limited by the device quality factor and back-reflection.
Article
Physics, Applied
Ashfaq Ahmad, Pawel Strak, Pawel Kempisty, Konrad Sakowski, Jacek Piechota, Yoshihiro Kangawa, Izabella Grzegory, Michal Leszczynski, Zbigniew R. Zytkiewicz, Grzegorz Muziol, Eva Monroy, Agata Kaminska, Stanislaw Krukowski
Summary: This work investigates the emergence of polarization doping in AlxGa1-xN layers with graded composition from a theoretical viewpoint. It shows that bulk electric charge density emerges in the graded concentration region and obtains the relation between the polarization bulk charge density and the concentration gradient. The study also demonstrates that a mobile charge appears due to the increase of the distance between opposite polarization-induced charges.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Tomasz Stefaniuk, Jan Suffczynski, Malgorzata Wierzbowska, Jaroslaw Z. Domagala, Jaroslaw Kisielewski, Andrzej Klos, Alexander Korneluk, Henryk Teisseyre
Summary: In this study, the optical, electronic, and structural properties of ScAlMgO4 are investigated using ScAlMgO4 single crystals grown by the Czochralski method. The results show that ScAlMgO4 has excellent refractive indices and lattice constants, making it a suitable material for low-threshold, deep-UV lasing devices.
Proceedings Paper
Optics
Nicola Roccato, Francesco Piva, Carlo De Santi, Riccardo Brescancin, Kalparupa Mukherjee, Matteo Buffolo, Camille Haller, Jean-Francois Carlin, Nicolas Grandjean, Marco Vallone, Alberto Tibaldi, Francesco Bertazzi, Michele Goano, Giovanni Verzellesi, Gaudenzio Meneghesso, Enrico Zanoni, Matteo Meneghini
Summary: This paper analyzes the impact of defects on the electrical characteristics of InGaN light-emitting diodes (LEDs) and determines the energy levels and concentrations of these defects through simulation and measurement. The results show that these defects have a significant influence on the current-voltage characteristics of LEDs, especially in the sub turn-on region.
GALLIUM NITRIDE MATERIALS AND DEVICES XVII
(2022)
Proceedings Paper
Engineering, Manufacturing
Matteo Buffolo, Nicola Roccato, Francesco Piva, Carlo De Santi, Riccardo Brescancin, Claudia Casu, Alessandro Caria, Kalparupa Mukherjee, Camille Haller, Jean Francois Carlin, Nicolas Grandjean, Marco Vallone, Alberto Tibaldi, Francesco Bertazzi, Michele Goano, Giovanni Verzellesi, Mauro Mosca, Gaudenzio Meneghesso, Enrico Zanoni, Matteo Meneghini
Summary: This presentation discusses the experimental characterization of defect properties and the modeling of their impact on the electro-optical characteristics of III-N light-emitting diodes (LEDs).
LIGHT-EMITTING DEVICES, MATERIALS, AND APPLICATIONS XXVI
(2022)
Article
Materials Science, Multidisciplinary
R. Aristegui, F. Chiaruttini, B. Jouault, P. Lefebvre, C. Brimont, T. Guillet, M. Vladimirova, S. Chenot, Y. Cordier, B. Damilano
Summary: This study found that excitons in wide GaN/(Al, Ga)N quantum wells are made spatially indirect by a built-in electric field. The density of excitons in traps can be controlled by an external electric bias. Negative bias deepens the trapping potential, while positive bias releases the excitons.
Article
Materials Science, Multidisciplinary
F. Chiaruttini, T. Guillet, C. Brimont, D. Scalbert, S. Cronenberger, B. Jouault, P. Lefebvre, B. Damilano, M. Vladimirova
Summary: Using spatially resolved magnetophotoluminescence spectroscopy, we demonstrated the Mott transition from a dipolar excitonic to an electron-hole plasma state in a wide GaN/(Al,Ga)N quantum well at T = 7 K. The carrier density at the Mott transition was estimated to be approximately 2 x 10^(11) cm^(-2), and the role of excitonic correlations in this process was addressed. Unlike GaAs/(Al,Ga)As systems, where dipolar magnetoexciton transport is strongly quenched by the magnetic field, in GaN/(Al,Ga)N systems, the transport is preserved up to 9 T due to the band parameters.