Article
Physics, Applied
Matthieu Moret, Adrien Rousseau, Pierre Valvin, Sachin Sharma, Laurent Souqui, Henrik Pedersen, Hans Hogberg, Guillaume Cassabois, Jianhan Li, J. H. Edgar, Bernard Gil
Summary: Boron nitride (BN) layers with sp(2) bonding were grown by metal organic chemical vapor deposition on AlN underlayers, showing ordered rhombohedral (rBN) and partially ordered turbostratic (tBN) structures. The optical signature of tBN at 5.45eV appears between the two recombination bands typical of rBN at 5.35eV (strong intensity) and 5.55eV (weaker intensity), distinguishing from the hBN and bBN.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Physical
Alfredo Segura, Ramon Cusco, Claudio Attaccalite, Takashi Taniguchi, Kenji Watanabe, Luis Artus
Summary: The study investigated the pressure dependence of bandgap transitions in hexagonal boron nitride using optical reflectance. It was found that with increasing pressure, both direct and indirect bandgap transitions shift downwards, with the direct transition exhibiting a faster decrease. After considering excitonic effects, it was observed that the pressure coefficient of the direct excitonic transition is much lower than that of the indirect excitonic transition.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Adrien Rousseau, Pierre Valvin, Wilfried Desrat, Lianjie Xue, Jiahan Li, James H. Edgar, Guillaume Cassabois, Bernard Gil
Summary: The presence of metastable Bernal stacking boron nitride is confirmed by using second harmonic generation and photoluminescence spectroscopy. The study reveals the specific signature of the noncentrosymmetric Bernal stacking and demonstrates the coherent character of the Bernal phase in boron nitride crystals using two-photon excitation spectroscopy.
Article
Engineering, Electrical & Electronic
Roohoallah Zare, Hojat Allah Badehian
Summary: Density functional theory and the SIESTA code were used to investigate the electronic bandgap and optical spectra of zigzag boron nitride nanoribbons (n-ZBNNRs). The simulated nanoribbons were found to be semiconductors with a bandgap of 4.87-4.95 eV. The real part of the dielectric function suggested that ZBNNRs are negative refractive index materials. Additionally, the optical absorption of n-ZBNNRs was found to be anisotropic for different polarizations.
OPTICAL AND QUANTUM ELECTRONICS
(2023)
Article
Chemistry, Multidisciplinary
Chen Chen, Yang Hang, Hui Shan Wang, Yang Wang, Xiujun Wang, Chengxin Jiang, Yu Feng, Chenxi Liu, Eli Janzen, James H. Edgar, Zhipeng Wei, Wanlin Guo, Weida Hu, Zhuhua Zhang, Haomin Wang, Xiaoming Xie
Summary: The bandgap of hBN nanoribbons (BNNRs) can be changed by spatial/electrostatic confinement. Water adsorption greatly reduces the bandgap of zigzag-oriented BNNRs (zBNNRs) and can tune their conductance and optical bandgaps.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Qingyang Fan, Ruida Zhao, Yingbo Zhao, Yanxing Song, Sining Yun
Summary: In this study, eight BN polymorphs (2H, 4H, 5H, 6H-I, 6H-II, 7H-I, 7H-II, and 7H-III) were obtained using a random sampling strategy, and their similarities to 3C BN in stacking order were observed. The calculations showed that these polymorphs have high stability and thermal stability. Additionally, they exhibit superhard characteristics and can be considered as promising ultrawide-bandgap semiconductors.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Chemistry, Multidisciplinary
K. P. Korona, J. Binder, A. K. Dabrowska, J. Iwanski, A. Reszka, T. Korona, M. Tokarczyk, R. Stepniewski, A. Wysmolek
Summary: Defects in semiconductors play a critical role in their functional properties, and understanding and controlling these defects is essential for their application. This study investigates the UV luminescence of intentionally introduced defects in hexagonal boron nitride grown by MOVPE. Photoluminescence and cathodoluminescence experiments revealed several characteristic lines, including X230, C300, and C380, corresponding to well-known and rarely observed defect bands. The study also found that the color center bands C were replaced by broad bands D in samples grown at high temperatures, indicating a different defect formation mechanism. Time-resolved photoluminescence analysis provided insight into the lifetimes and phonon interaction of the different defect lines.
Article
Physics, Applied
Qingyang Fan, Nan Wu, Runling Yang, Wei Zhang, Xinhai Yu, Sining Yun
Summary: This study investigated four new boron nitride polymorphs with sp(2) hybridization, revealing them as wide bandgap semiconductor materials with stable mechanical properties and different degrees of anisotropy in Young's modulus. These polymorphs show promising potential for various technological applications due to their unique electronic and structural properties.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Samir F. Matar, Vladimir L. Solozhenko
Summary: The study utilizes density functional theory and geometry optimization to calculate the properties of rhombohedral carbon and boron nitride, identifying both phases as ultra-hard materials with distinct differences in electronic band structures.
DIAMOND AND RELATED MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
H. Plaisantin, S. Jacques, J. Danet, G. Camus, H. Delpouve
Summary: The BN interphases synthesized by CVI at 900 and 1200 degrees C exhibit varying degrees of crystallization and microstructure, affecting the growth of the SiC matrix in different ways.
MATERIALS CHARACTERIZATION
(2021)
Article
Chemistry, Multidisciplinary
Ping Wang, Woncheol Lee, Joseph P. Corbett, William H. Koll, Nguyen M. Vu, David Arto Laleyan, Qiannan Wen, Yuanpeng Wu, Ayush Pandey, Jiseok Gim, Ding Wang, Diana Y. Qiu, Robert Hovden, Mackillo Kira, John T. Heron, Jay A. Gupta, Emmanouil Kioupakis, Zetian Mi
Summary: This study proposes a growth process mediated by an hBN/G interface for the controlled synthesis of high-quality monolayer hBN. The scalable epitaxy of unidirectional monolayer hBN on graphene aligned to the underlying graphene lattice is achieved. Additionally, it is discovered that monolayer hBN exhibits deep-ultraviolet emission with a giant renormalized direct bandgap on graphene.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Analytical
Baha Ondes, Cagdas Sunna, Ulviye Kilimci, Murat Uygun, Deniz Aktas Uygun
Summary: In this study, enzyme-modified boron nitride nanosheets were developed as a catalytic two-dimension material for sensor applications. The developed enzyme-based biosensor exhibited wide linear detection range, low limit of detection and quantitation values, good reproducibility, reusability, high selectivity, sensitivity, low Km value, and excellent shelf-life properties. It has also successfully identified uric acid in human serum with high recovery rate, promising rapid and high sensitivity applications in real serum.
MICROCHEMICAL JOURNAL
(2023)
Article
Materials Science, Multidisciplinary
Jean Paul Nery, Matteo Calandra, Francesco Mauri
Summary: This study investigates the energetics of multilayer stacked graphene using first-principles calculations, revealing the critical role of electronic temperature in determining the stability of BG and RG. Low energy states at room temperature consist of BG, RG, and mixed BG-RG systems, with Ising model analysis providing insights into the ordering of stacking sequences. This work clarifies inconsistencies in the literature and lays the foundation for studying external factors' effects on the stability of multilayer graphene systems in first principles calculations.
Article
Multidisciplinary Sciences
Qiucheng Li, Venkata Surya Chaitanya Kolluru, Matthew S. Rahn, Eric Schwenker, Shaowei Li, Richard G. Hennig, Pierre Darancet, Maria K. Y. Chan, Mark C. Hersam
Summary: This study reports the synthesis of borophane polymorphs by hydrogenating borophene with atomic hydrogen, revealing their specific bonding modes and metallic properties. The borophane polymorphs can be reversibly returned to pristine borophene through thermal desorption of hydrogen, and also provide a chemical passivation effect by reducing oxidation rates.
Article
Materials Science, Multidisciplinary
Lyubov Kotova, Linar A. Altynbaev, Maria O. Zhukova, Bogdan R. Borodin, Vladimir P. Kochereshko, Anna Baldycheva, Benjamin T. Hogan
Summary: Unusual optical anisotropy was observed in hexagonal boron nitride thin films produced via ultrasonication. Statistical analysis revealed an ordered particle density distribution corresponding to the observed optical axis.
Article
Physics, Applied
B. Damilano, S. Vezian, M. P. Chauvat, P. Ruterana, N. Amador-Mendez, S. Collin, M. Tchernycheva, P. Valvin, B. Gil
Summary: InGaN/GaN single quantum wells grown on silicon substrates with thin AlN and GaN buffer layers were made nanoporous using SixNy nanomasking and sublimation, leading to a significant improvement in photoluminescence efficiency.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Yang Ge, Lingxiu Chen, Chengxin Jiang, Jianlong Ji, Qiuyun Tan, Douxing Pan, Wendong Zhang, Riguang Zhang, Eli Janzen, James H. Edgar, Shengbo Sang, Haomin Wang
Summary: In this study, triangular zigzag-edged graphene nanoflakes (GNFs) were successfully synthesized and found to exhibit high magnetization. Density functional theory calculations revealed that this magnetic property is a result of superexchange interactions among unpaired electrons at the zigzag C-BN interface. This research provides a promising platform for experimentally achieving GNFs with high electron spin states.
Article
Chemistry, Multidisciplinary
Hanan Herzig Sheinfux, Minwoo Jung, Lorenzo Orsini, Matteo Ceccanti, Aditya Mahalanabish, Daniel Martinez-Cercos, Iacopo Torre, David Barcons Ruiz, Eli Janzen, James H. Edgar, Valerio Pruneri, Gennady Shvets, Frank H. L. Koppens
Summary: This study successfully created nanoscale hypercrystals, and measured the Bloch modes of these crystals directly using scattering near-field microscopy. The dispersion of the Bloch modes was extracted and revealed a clear switch from positive to negative group velocity. The study also observed spectral features specific to hypercrystals, providing important insights into nanoscale light-matter interactions and the manipulation of optical density.
Article
Chemistry, Multidisciplinary
Alexey Y. Nikitin, Rainer Hillenbrand, Andrei Bylinkin, Francesco Calavalle, Maria Barra-Burillo, Roman V. Kirtaev, Elizaveta Nikulina, Evgeny Modin, Eli Janzen, James H. Edgar, Felix Casanova, Luis E. Hueso, Valentyn S. Volkov, Paolo Vavassori, Igor Aharonovich, Pablo Alonso-Gonzalez
Summary: Strong coupling between light and matter excitations in both mid-IR and visible frequency bands is achieved by introducing polaritonic nanoresonators, which can manipulate material properties and have potential applications in optoelectronics, nanophotonics, and quantum information.
Article
Nanoscience & Nanotechnology
B. Damilano, S. Vezian, J. Brault, P. Ruterana, B. Gil, M. Tchernycheva
Summary: Nanoporous GaN layers were successfully fabricated using selective area sublimation with an AlN nanomask. The porosity of the layers could be adjusted by changing the nanomask thickness and sublimation conditions. The porous GaN layers showed improved room temperature photoluminescence properties, especially in the 0.4-0.65 porosity range. The characteristics of these porous layers were compared to those obtained with a Si(x)N(y) nanomask, and the regrowth of p-type GaN on light emitting diode structures made porous with different nanomasks were also compared.
Article
Multidisciplinary Sciences
A. J. Sternbach, S. L. Moore, A. Rikhter, S. Zhang, R. Jing, Y. Shao, B. S. Y. Kim, S. Xu, S. Liu, J. H. Edgar, A. Rubio, C. Dean, J. Hone, M. M. Fogler, D. N. Basov
Summary: We visualized negative refraction of phonon polaritons, which occur when passing through a planar interface between molybdenum oxide (MoO3) and isotopically pure hexagonal boron nitride (h11BN). The polaritons, hybrids of infrared photons and lattice vibrations, form collimated rays that exhibit negative refraction. These rays can circulate along closed diamond-shaped trajectories at a specific frequency co0. We found that the polariton eigenmodes display regions of both positive and negative dispersion, with multiple gaps resulting from polaritonic-level repulsion and strong coupling.
Article
Chemistry, Multidisciplinary
Eli Janzen, Hannah Schutte, Juliette Plo, Adrien Rousseau, Thierry Michel, Wilfried Desrat, Pierre Valvin, Vincent Jacques, Guillaume Cassabois, Bernard Gil, James H. Edgar
Summary: The changes in the properties of hexagonal boron nitride (hBN) induced by isotopic purification are reported. The study extends the purification to N-15 isotopes. Raman and photoluminescence spectroscopies show that the monoisotopic hBN crystals exhibit similar vibrational and optical properties to N-14 purified hBN. The growth of high-quality h(10)B(14)N, h(11)B(14)N, h(10)B(15)N, and h(11)B(15)N crystals opens up new possibilities for thermal conductivity control and advanced functionalities in quantum technologies.
ADVANCED MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Taoufiq Ouaj, Leonard Kramme, Marvin Metzelaars, Jiahan Li, Kenji Watanabe, Takashi Taniguchi, James H. Edgar, Bernd Beschoten, Paul Koegerler, Christoph Stampfer
Summary: This work demonstrates the growth of hBN crystals using an iron flux and their potential for high-performance hBN-graphene devices. The crystals can be detached from the metal using hydrochloric acid, and they exhibit excellent quality for van der Waals heterostructures. The thickness of exfoliated hBN flakes does not correlate with their quality in high mobility graphene devices.
Article
Multidisciplinary Sciences
M. Chen, Y. Zhong, E. Harris, J. Li, Z. Zheng, H. Chen, J. -S. Wu, P. Jarillo-Herrero, Q. Ma, J. H. Edgar, X. Lin, S. Dai
Summary: In this study, the authors propose a method to engineer material properties by repositioning isotopes in engineered van der Waals isotopic heterostructures. By varying the composition, stacking order, and thicknesses of h(10)BN and h(11)BN building blocks, the energy-momentum dispersions of hyperbolic phonon polaritons can be modulated. These tailored polaritons have promising applications in nanophotonics and thermal functionalities.
NATURE COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Alexey Falin, Haifeng Lv, Eli Janzen, James H. Edgar, Rui Zhang, Dong Qian, Hwo-Shuenn Sheu, Qiran Cai, Wei Gan, Xiaojun Wu, Elton J. G. Santos, Lu Hua Li
Summary: This study uses single-atom-thin hBN to investigate the mechanical properties of materials and finds that the lighter isotope 10B exhibits higher elasticity and strength compared to the heavier isotope 11B. This suggests that two-dimensional materials can be used to study the intrinsic mechanical properties of materials, and the normally neglected isotopic perturbation sometimes plays a more critical role than the isotopic mass effect in the mechanical and other physical properties. Two-dimensional materials can serve as good platforms for studying extremely subtle mechanical behaviors.
NATURE COMMUNICATIONS
(2023)
Article
Nanoscience & Nanotechnology
Sachin Sharma, Song Liu, James H. Edgar, Ioannis Chatzakis
Summary: Hexagonal boron nitride (hBN) is a semiconductor material with promising applications due to its strong luminescence. The dynamics of photogenerated carriers in hBN were analyzed, and Auger recombination and defect-assisted recombination were identified as the main mechanisms affecting carrier kinetics.
Article
Chemistry, Physical
Peter Udvarhelyi, Tristan Clua-Provost, Alrik Durand, Jiahan Li, James H. H. Edgar, Bernard Gil, Guillaume Cassabois, Vincent Jacques, Adam Gali
Summary: Researchers determine the coupling of boron-vacancy spin defect (V-B(-)) in hexagonal boron nitride (hBN) to strain and electric fields using first-principles calculations. Their work reveals the interplay between local piezoelectric and elastic effects in the response to electric fields. Theoretical predictions are used to analyze optically detected magnetic resonance (ODMR) spectra on hBN crystals with varying densities of V-B(-) centers, confirming that the orthorhombic zero-field splitting parameter is a result of local electric fields from surrounding charge defects. This study paves the way for applications of V-B(-) centers in quantitative electric field imaging and quantum sensing under pressure.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Lama Khalil, Cyrine Ernandes, Jose Avila, Adrien Rousseau, Pavel Dudin, Nikolai D. Zhigadlo, Guillaume Cassabois, Bernard Gil, Fabrice Oehler, Julien Chaste, Abdelkarim Ouerghi
Summary: In this study, we demonstrate the stable growth of p-type hexagonal boron nitride (h-BN) by using Mg atoms as substitutional impurities. Our experiments involving micro-Raman spectroscopy, nano-ARPES, and KPFM show that Mg-doping significantly alters the electronic properties of h-BN. The Mg dopants shift the valence band maximum and result in a reduced Fermi level difference between pristine and Mg-doped h-BN crystals. This research establishes Mg-doping as a promising method for high-quality p-type doped h-BN films, which are crucial for applications in deep ultraviolet LEDs and wide bandgap optoelectronic devices.
NANOSCALE ADVANCES
(2023)
Article
Multidisciplinary Sciences
Mingze He, Joseph R. Matson, Mingyu Yu, Angela Cleri, Sai S. Sunku, Eli Janzen, Stefan Mastel, Thomas G. Folland, James H. Edgar, D. N. Basov, Jon-Paul Maria, Stephanie Law, Joshua D. Caldwell
Summary: Doped semiconductor substrates, such as InAs and CdO, enable significant tuning and dynamic modulation of hyperbolic phonon polaritons (HPhPs). By altering the photo-injected carriers in the substrate, HPhPs can be tuned with a maximum difference of 8.3 times. This study presents an important advancement in manipulating HPhPs.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Samuel W. LaGasse, Nicholas V. Proscia, Cory D. Cress, Jose J. Fonseca, Paul D. Cunningham, Eli Janzen, James H. Edgar, Daniel J. Pennachio, James Culbertson, Maxim Zalalutdinov, Jeremy T. Robinson
Summary: This study demonstrates that hBN slabs tuned to the correct thickness can act as optical waveguides, enabling direct coupling of light emission from encapsulated layers into waveguide modes. Experimental and theoretical approaches provide essential details for leveraging hBN slab waveguides in future research and applications.
ADVANCED MATERIALS
(2023)
