Article
Physics, Applied
Y. Wang, T. Sohier, K. Watanabe, T. Taniguchi, M. J. Verstraete, E. Tutuc
Summary: Electron transport measurements were conducted on dual-gated monolayer WS2 encapsulated in hexagonal boron-nitride. The study revealed a strong temperature dependence of mobility at high temperatures due to phonon scattering, and a saturation of mobility at low temperature caused by impurity and long-range Coulomb scattering. Experimental results were in good agreement with first-principles calculations, indicating proximity to the intrinsic limit of transport in these two-dimensional layers.
APPLIED PHYSICS LETTERS
(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
Materials Science, Multidisciplinary
Jun Ge, Haiming Huang, Zelin Ma, Weilong Chen, Xucheng Cao, Huaheng Fang, Jianfeng Yan, Zhiyu Liu, Weiliang Wang, Shusheng Pan
Summary: This study introduces an interface engineering strategy by inserting an interfacial polymer layer between monolayer hexagonal boron nitride and top electrodes, which successfully improves the performance of vertical memristive devices based on single-layer materials. The device demonstrates stable resistive switching behavior with low operating voltage, high on/off ratio, long retention time, and excellent flexibility, showing promising potential for large-scale integrated ultrathin flexible memory applications.
MATERIALS & DESIGN
(2021)
Article
Nanoscience & Nanotechnology
Biying Tan, You Wu, Feng Gao, Huihui Yang, Yunxia Hu, Huiming Shang, Xin Zhang, Jia Zhang, Zhonghua Li, YongQing Fu, Dechang Jia, Yu Zhou, Haiying Xiao, PingAn Hu
Summary: In this study, a new method was reported to enhance the optoelectronic properties of hBN monolayers by substitutively doping with sulfur on a molten Au substrate. The S atoms were more favorable to be doped in the N sites of hBN and formed a new conduction band edge, narrowing the band gap. The doping of sulfur improved the conductivity and optoelectronic properties of hBN.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Physical
Qingzhong Gui, Zhen Wang, Zhaofu Zhang, Liu Xie, Xiaoming Zha, Jun Wang, Yuzheng Guo
Summary: In this study, a category of 2D materials called graphenelike monolayer monoxides, monochlorides, and mononitrides (GLMMs) are systematically studied using density functional theory and density functional perturbation theory. The stability of different native point defects in GLMMs is investigated energetically, showing their outstanding structural stability and high resistance to vacancy formation. The dielectric properties of GLMMs are explored and found to be promising for device applications.
CHEMISTRY OF MATERIALS
(2023)
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
Optics
Zeinab Eftekhari, Amir Ghobadi, Mahmut Can Soydan, Deniz Umut Yildirim, Neval Cinel, Ekmel Ozbay
Summary: In this study, strong light emission from defective hexagonal boron nitride defect centers was demonstrated upon coupling with near-touching plasmonic units. The proposed plasmonic design at thin layer thicknesses of 20 nm can provide over 2 orders of magnitude enhancement in photoluminescence spectra and shorten the luminescence lifetime of the emitters. This plasmonic platform can be easily extended to other plasmonic-emitter combinations for achieving strong light-matter interaction using large-scale compatible routes.
Review
Chemistry, Multidisciplinary
Soumyabrata Roy, Xiang Zhang, Anand B. Puthirath, Ashokkumar Meiyazhagan, Sohini Bhattacharyya, Muhammad M. Rahman, Ganguli Babu, Sandhya Susarla, Sreehari K. Saju, Mai Kim Tran, Lucas M. Sassi, M. A. S. R. Saadi, Jiawei Lai, Onur Sahin, Seyed Mohammad Sajadi, Bhuvaneswari Dharmarajan, Devashish Salpekar, Nithya Chakingal, Abhijit Baburaj, Xinting Shuai, Aparna Adumbumkulath, Kristen A. Miller, Jessica M. Gayle, Alec Ajnsztajn, Thibeorchews Prasankumar, Vijay Vedhan Jayanthi Harikrishnan, Ved Ojha, Harikishan Kannan, Ali Zein Khater, Zhenwei Zhu, Sathvik Ajay Iyengar, Pedro Alves da Silva Autreto, Eliezer Fernando Oliveira, Guanhui Gao, A. Glen Birdwell, Mahesh R. Neupane, Tony G. Ivanov, Jaime Taha-Tijerina, Ram Manohar Yadav, Sivaram Arepalli, Robert Vajtai, Pulickel M. Ajayan
Summary: Hexagonal boron nitride (h-BN) is a strong candidate for two-dimensional (2D) materials due to its exciting optoelectrical properties, combined with mechanical robustness, thermal stability, and chemical inertness. Various synthesis strategies for 2D h-BN, including chemical exfoliation, chemical, and physical vapor deposition, have been developed in recent years. The potential applications of h-BN structures in nanoelectronics, photonics, biomedical, anti-corrosion, and catalysis are described based on their extraordinary properties and stability.
ADVANCED MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
Prabath Hewageegana
Summary: This theoretical study examines the interaction between an ultrafast intense circularly polarized optical pulse and monolayer hexagonal Boron Nitride (h-BN), revealing a topological origin for the fastest valley polarization generation in this material. The valley polarization and residual conduction band population decrease and vanish after a certain pulse duration, leading to the creation of a new interference pattern in reciprocal space. The ultrafast valley polarization observed in monolayer h-BN may have implications for petahertz-band information processing.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2021)
Article
Materials Science, Multidisciplinary
Yifan Ding, Junkai Yang, Huaixiang Wang, Yu Ji, Qinwen Guo, Weipeng Wang, Xi Shen, Yuan Yao, Richeng Yu
Summary: The density of antisite defects significantly affects the stability of monolayer hexagonal boron nitride, influencing the crystal structure and electronic structure, as well as the energy level transitions between atoms.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2021)
Article
Chemistry, Physical
Hua Wen, Boyang Wang, Xingjia Cheng, Dan Song, Huan Xiao, Wen Xu, Siyu Lu
Summary: In this study, CNDs/ML-hBN/sapphire heterostructures were fabricated and characterized for their basic physical and chemical properties, as well as their optical conductivity and temperature dependence. The study found that the presence of ML-hBN can suppress the agglomeration of dried CNDs on sapphire substrate and effectively control and modulate the electronic and optoelectronic properties of the heterostructures. These findings are important for the fabrication, integration, and modulation of CND based vdW heterostructures for practical device applications.
APPLIED SURFACE SCIENCE
(2023)
Article
Physics, Condensed Matter
Roudabeh Mohsseni Ahangar, Davood Farmanzadeh
Summary: With density functional theory calculations, the structural and electronic properties of Cu, Li, and O-doped phosphorene/hexagonal boron nitride systems were investigated. The addition of hexagonal boron nitride layers did not alter the intrinsic physical properties of pristine phosphorene layer. However, doping of phosphorene resulted in stronger binding energy at the interface, enhancing the stability of the doped phosphorene/hexagonal boron nitride systems. Doping also caused changes in the electronic properties, with a decrease in band gap and transformation from semiconductor to metallic behavior, making these systems suitable for electronic and optical applications.
PHYSICA B-CONDENSED MATTER
(2023)
Article
Chemistry, Multidisciplinary
Mohammad Mahdi Tavakoli, Ji-Hoon Park, Jeremiah Mwaura, Mayuran Saravanapavanantham, Vladimir Bulovic, Jing Kong
Summary: This study suggests monolayer h-BN grown via CVD as an effective replacement for HTLs in the fabrication of efficient inverted OPVs. The use of h-BN creates smaller barriers for holes and larger barriers for electrons, allowing for efficient charge separation and stability in the devices.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Optics
Muhammad Bilal, Wen Xu, Hua Wen, Xingjia Cheng, Yiming Xiao, Lan Ding
Summary: This study demonstrates, for the first time, the observation of the optical Hall effect (OHE) in p-type monolayer hexagonal boron nitride (hBN) under linearly polarized tera-hertz irradiation on a fused silica substrate. The enhancement of Rashba spin-orbit coupling, inducing in-plane spin component and lifting of valley degeneracy, leads to the nonzero transverse optical conductivity in the presence of linearly polarized THz radiation.
Article
Chemistry, Multidisciplinary
Johannes E. Froech, Lesley P. Spencer, Mehran Kianinia, Daniel D. Totonjian, Minh Nguyen, Andreas Gottscholl, Vladimir Dyakonov, Milos Toth, Sejeong Kim, Igor Aharonovich
Summary: Color centers in hexagonal boron nitride (hBN) have shown efficient coupling to bullseye cavities, demonstrating a 6.5-fold enhancement in boron vacancy spin defects. Through finite-difference time-domain modeling, emission dipole orientation and enhanced contrast in optically detected magnetic resonance readout have been elucidated. This paves the way for integrating hBN spin defects with photonic resonators for a scalable spin-photon interface.
Article
Multidisciplinary Sciences
Darshana Wickramaratne, I. I. Mazin
Summary: In this study, the authors provide an alternative explanation for the non-monotonic behavior of the superconducting transition temperature in NbSe2-xSx monolayer alloys based on the effects of alloying and defects on the electronic structure and magnetism.
NATURE COMMUNICATIONS
(2022)
Article
Nanoscience & Nanotechnology
Connie H. Li, Jisoo Moon, Olaf M. J. van't Erve, Darshana Wickramaratne, Enrique D. Cobas, Michelle D. Johannes, Berend T. Jonker
Summary: Current-generated spin in topological insulator surface states can switch the magnetization of an adjacent ferromagnet efficiently. However, most of the current in FM/TI heterostructures is shunted through the ferromagnetic metal. Placing an insulating layer between the topological insulator and ferromagnetic metal can prevent current shunting and preserve the topological surface states.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Physics, Applied
Darshana Wickramaratne, Joel B. Varley, John L. Lyons
Summary: This study examines the prospects for n-type doping in corundum (AlxGa1-x)(2)O-3 alloys using first-principles calculations. It is found that Si and Hf can remain shallow donors even when the alloy bandgap exceeds 6.5 eV. The detrimental role of cation vacancies as compensating deep acceptors is also addressed, and a potential solution using doping in a hydrogen-rich environment under cation-rich conditions is suggested.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Hsun-Jen Chuang, Madeleine Phillips, Kathleen M. McCreary, Darshana Wickramaratne, Matthew R. Rosenberger, Vladimir P. Oleshko, Nicholas Proscia, Mark Lohmann, Dante J. O'Hara, Paul D. Cunningham, C. Stephen Hellberg, Berend T. Jonker
Summary: The appearance of moire Raman modes from nearly aligned WSe2-WS2 van der Waals heterostructures in a certain frequency range indicates sensitivity to twist angle and strong Raman intensity modulation dependent on excitation energy and temperature. These modes exhibit identical frequencies for a given small twist angle and are a consequence of the large moire length scale resulting in zone-folded phonon modes that are Raman active.
Correction
Physics, Applied
Darshana Wickramaratne, Joel B. B. Varley, John L. L. Lyons
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Darshana Wickramaratne, I. I. Mazin
Summary: The recent discovery of Ising superconductivity has generated significant interest due to its resistance to large in-plane magnetic fields. This Perspective provides a comprehensive understanding of Ising superconductors, including their basic concepts, electronic structure, and magnetic properties. Key experimental observations in this class of superconductors are summarized, along with the influence of defects and proximity-induced effects at interfaces on Ising superconductivity. The prospects of observing Ising superconductivity in bulk materials are also discussed.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Su-Hyun Yoo, Mira Todorova, Jorg Neugebauer, Chris G. Van de Walle
Summary: GaN/(Al, Ga)N heterojunctions are crucial for high-electron-mobility transistors. The density of the two-dimensional electron gas (2DEG) on the GaN side is significantly enhanced by the strong polarization fields at the interface. The source of the electrons in the 2DEG is intrinsic to the overall structure and the negative charge is balanced by fixed charge on the surface, rather than surface states.
PHYSICAL REVIEW APPLIED
(2023)
Article
Quantum Science & Technology
Mehmet T. Uysal, Mouktik Raha, Songtao Chen, Christopher M. Phenicie, Salim Ourari, Mengen Wang, Chris G. Van de Walle, Viatcheslav V. Dobrovitski, Jeff D. Thompson
Summary: In this work, coherent coupling between the electron spin of a single Er3+ ion and a single I = 1/2 nuclear spin in the solid-state host crystal, which is a fortuitously located proton (1H), is demonstrated. The nuclear spin is controlled using dynamical-decoupling sequences applied to the electron spin, allowing for one- and two-qubit gate operations. The longer coherence time of the nuclear spin, compared to the electron spin, is crucial for combining long-lived nuclear spin quantum registers with telecom-wavelength emitters for long-distance quantum repeaters.
Correction
Physics, Applied
Darshana Wickramaratne, Cyrus E. Dreyer, Bartomeu Monserrat, Jimmy-Xuan Shen, John L. Lyons, Audrius Alkauskas, Chris. G. van de Walle
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Multidisciplinary
Fangzhou Zhao, Mark E. Turiansky, Audrius Alkauskas, Chris G. Van de Walle
Summary: Trap-assisted Auger-Meitner recombination is highlighted as a dominant nonradiative process in wide-band-gap materials, and a first-principles methodology is presented to determine the rates of this process in semiconductors or insulators due to defects or impurities.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Ymir K. Frodason, Joel B. Varley, Klaus Magnus H. Johansen, Lasse Vines, Chris G. Van de Walle
Summary: Pathways and energy barriers for the migration of Ga vacancies (VGa) and Ga interstitials (Gai) in-Ga2O3 have been studied using hybrid functional calculations and the nudged elastic band method. A mechanism for the transformation of VGa between different split configurations has been described. The overall migration barriers for VGa and Gai in different crystal directions have been determined. The results provide insights into the thermally activated recovery processes in irradiated material.
Article
Materials Science, Multidisciplinary
Yubi Chen, Mark E. Turiansky, Chris G. Van de Walle
Summary: This study conducted comprehensive investigations on native point defects in beryllium oxide (BeO) using density functional theory. The stability and potential applications of different defects were analyzed, and suitable candidates for quantum defects were identified.
Article
Quantum Science & Technology
Raj N. Patel, David A. Hopper, Jordan A. Gusdorff, Mark E. Turiansky, Tzu-Yung Huang, Rebecca E. K. Fishman, Benjamin Porat, Chris G. Van de Walle, Lee C. Bassett
Summary: By using photon emission correlation spectroscopy, we revealed the optical dynamics of quantum emitters in hexagonal boron nitride. The experimental results showed the existence of quantum emitters with ideal single-photon emission and their photoluminescence emission lineshapes were consistent with individual vibronic transitions. However, polarization-resolved excitation and emission revealed the role of multiple optical transitions, and photon emission correlation spectroscopy revealed the complicated optical dynamics associated with excitation and relaxation.
Proceedings Paper
Engineering, Electrical & Electronic
Mengen Wang, Sai Mu, Chris G. Van de Walle
Summary: This paper discusses the diffusion behavior of dopants and point defects in monoclinic gallium oxide, as well as the diffusion of hydrogen in gallium oxide. The results provide important guidance for controlling doping in gallium oxide and its alloys.
OXIDE-BASED MATERIALS AND DEVICES XIII
(2022)
Article
Materials Science, Multidisciplinary
Sai Mu, Mengen Wang, Joel B. Varley, John L. Lyons, Darshana Wickramaratne, Chris G. Van de Walle
Summary: We used hybrid density functional calculations to analyze n-type doping in monoclinic (AlxGa1-x)(2)O-3 alloys. Our study focused on the impact of silicon, carbon, and hydrogen as impurities in metal-organic chemical vapor deposition (MOCVD) and their effect on the structural properties and charge-state transition levels of the alloys.
