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Synthesis and photoluminescence properties of hexagonal BGaN alloys and quantum wells
摘要： Hexagonal boron nitride (h-BN) has emerged as an important extreme bandgap semiconductor as well as a two-dimensional material. Achieving the ability for tuning the optoelectronic properties through alloying and heterojunction will further expand the applications of h-BN. By utilizing h-BN epilayer as a template, the synthesis of BN-rich B1?xGaxN alloys and quantum wells crystalized in the hexagonal phase has been demonstrated for the first time by metal organic chemical vapor deposition. The incorporation of Ga tends to enhance the conductivity. A blue shift in the band-edge emission upon the formation of h-BN/BGaN/BN QW has been observed, indicating the feasibility for heterojunction formation.
关键词： hexagonal boron nitride,MOCVD,photoluminescence,BGaN alloys,quantum wells
更新于2025-09-09 09:28:46
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Towards epitaxial graphene p-n junctions as electrically programmable quantum resistance standards
摘要： We report the fabrication and measurement of top gated epitaxial graphene p-n junctions where exfoliated hexagonal boron nitride (h-BN) is used as the gate dielectric. The four-terminal longitudinal resistance across a single junction is well quantized at the von Klitzing constant RK with a relative uncertainty of 10?7. After the exploration of numerous parameter spaces, we summarize the conditions upon which these devices could function as potential resistance standards. Furthermore, we offer designs of programmable electrical resistance standards over six orders of magnitude by using external gating.
关键词： p-n junctions,quantum resistance standards,gate dielectric,hexagonal boron nitride,epitaxial graphene
更新于2025-09-09 09:28:46
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[IEEE 2018 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Austin, TX, USA (2018.9.24-2018.9.26)] 2018 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - A Compact Model of Drift and Diffusion Memristor Applied in Neuron Circuits Design
摘要： A compact model of memristor for unifying two switch characteristics, drift and diffusion has been proposed, based on the ion dynamic transport theory at the oxide interface layer. The model is verified by measured data in different oxide-material-based drift/diffusion memristors, and well fits DC/AC characteristics of both devices, under parameter variations and temperature evolution. Moreover, the applications of this model in neuron circuits design are shown.
关键词： adsorption effect,boron nitride nanotubes,first-principles calculations,small molecule
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Budapest (2018.7.1-2018.7.5)] 2018 IEEE 2nd International Conference on Dielectrics (ICD) - High Voltage Electrical Properties of Epoxy / h-BN Microcomposites
摘要： Two high voltage properties – DC conductivity and AC breakdown strength – of epoxy composites filled with 30 wt% of micron sized hexagonal boron nitride (h-BN) are discussed in comparison to neat epoxy. The influence of h-BN upon the field dependence of DC conductivity has been studied up to 18 kV/mm. The addition of h-BN does not lead to a modification of conduction mechanisms: the J-V characteristics show an ohmic behavior at low fields and a space charge limited current (SCLC) at higher fields for both neat epoxy and composite. However, the addition of 30 wt% h-BN reduces the overall electrical conductivity and increases the threshold voltage between ohmic and SCLC regions, leading to a significant modification of electrical conductivity within the field range compared to neat epoxy. AC breakdown strength is enhanced for epoxy – h-BN composites while generally speaking the addition of micro fillers in an epoxy matrix tends to decrease it.
关键词： DC conductivity,electrical conduction mechanisms,epoxy composites,hexagonal boron nitride,AC breakdown strength
更新于2025-09-09 09:28:46
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Photonic Nanostructures from Hexagonal Boron Nitride
摘要： Growing interest in devices based on layered van der Waals (vdW) materials is motivating the development of new nanofabrication methods. Hexagonal boron nitride (hBN) is one of the most promising materials for studies of quantum photonics and phonon polaritonics. A promising nanofabrication process used to fabricate several hBN photonic devices using a hybrid reactive ion etching (RIE) and electron beam-induced etching (EBIE) technique is reported in detail here. The shortcomings and benefits of RIE and EBIE are highlighted and the utility of the hybrid approach for the fabrication of suspended and supported device structures with nanoscale features and highly vertical sidewalls are demonstrated. Functionality of the fabricated devices is proven by measurements of high-quality cavity optical modes (Q ≈ 1500). This nanofabrication approach constitutes an advance toward an integrated, monolithic quantum photonics platform based on hBN and other layered vdW materials.
关键词： hexagonal boron nitride,photonic devices,nanofabrication,nanophotonics,layered materials
更新于2025-09-04 15:30:14
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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Hydrothermal assembly of one-dimensional boron nitride nanostructures
摘要： Boron nitride (BN) is a state-of-the-art ultrawide bandgap semiconducting material. One-dimensional (1D) boron nitride nanostructures have high thermal conductivity (~600 W/mK) and wide band gap (5~6eV), which make it a promising thermal interface material. The 1D BN nanostructures were usually synthesized with chemical vapor deposition, restricted by the low yield and the high cost. Herein, we present a facile hydrothermal method to get 1D BN nanostructures. In the hydrothermal process, 2D BN nanosheets were firstly exfoliated from the BN powder, and then curled into 1D BN nanostructure through the chemical etching with sodium hydroxide. The alternative approach exhibited a high yield and a high concentration, which should be meaningful for the fabrication of 1D BN nanostructures.
关键词： One-dimensional nanostructure,Hydrothermal exfoliation,Chemical etching,Boron nitride
更新于2025-09-04 15:30:14
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Quantitative determination of a model organic/insulator/metal interface structure
摘要： By combining X-ray photoelectron spectroscopy, X-ray standing waves and scanning tunneling microscopy, we investigate the geometric and electronic structure of a prototypical organic/insulator/metal interface, namely cobalt porphine on monolayer hexagonal boron nitride (h-BN) on Cu(111). Specifically, we determine the adsorption height of the organic molecule and show that the original planar molecular conformation is preserved in contrast to the adsorption on Cu(111). In addition, we highlight the electronic decoupling provided by the h-BN spacer layer and find that the h-BN–metal separation is not significantly modified by the molecular adsorption. Finally, we find indication of a temperature dependence of the adsorption height, which might be a signature of strongly-anisotropic thermal vibrations of the weakly bonded molecules.
关键词： hexagonal boron nitride,X-ray standing waves,X-ray photoelectron spectroscopy,cobalt porphine,Cu(111),scanning tunneling microscopy,organic/insulator/metal interface
更新于2025-09-04 15:30:14
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Primitive and O-functionalized R-graphyne-like BN sheet: Candidates for SO <sub/>2</sub> Sensor with High Sensitivity and Selectivity at Room Temperature
摘要： In recent years, the successful obtained of various boron nitride allotropes have raised exciting prospects of 2D material for nano device area. Herein, two novel two-dimensional boron nitride allotropes, a rectangular graphyne-like sheet (R-BNyne) and an O-functionalized R-BNyne nanosheet (R-BNOyne), are proposed and investigated by first principle calculations. The structural stabilities of metallic R-BNyne and indirect gap semiconducting R-BNOyne are proved through the phonon dispersion and Molecular Dynamic calculations. Furthermore, the adsorptions of CH4, CO, CO2, SO2 and H2 on R-BNyne and R-BNOyne have been calculated to explore the possibilities of being as gas sensors. The significant change of the current-voltage curve with and without SO2 adsorption on R-BNyne and R-BNOyne implies that both of them could be used as candidates for SO2 superior sensor with high sensitivity and selectivity at room temperature. Our studies not only reveal a new solution to modulate the electronic properties of 2D nanosheets, but also are helpful for designing novel boron nitride allotropes for expanding the possibilities of being as gas sensors as well as superior capturer of SO2 with high sensitivity.
关键词： O-functionalized,R-graphyne-like boron nitride sheet,Electronic properties,Sensor,In-plane stiffness
更新于2025-09-04 15:30:14
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monolayers on the hBN-layer thickness
摘要： The optical properties of two-dimensional transition-metal dichalcogenide monolayers, such as MoS2 or WSe2 are dominated by excitons, Coulomb bound electron-hole pairs. Screening effects due to the presence of hexagonal-boron nitride (hBN) surrounding layers have been investigated by solving the Bethe-Salpeter equation on top of GW wave functions in density functional theory calculations. We have calculated the dependence of both the quasiparticle gap and the binding energy of the neutral exciton ground-state Eb as a function of the hBN-layer thickness. This paper demonstrates that the effects of screening at this level of theory are more short ranged than is widely believed. The encapsulation of a WSe2 monolayer by three sheets of hBN (～1 nm) already yields a 20% decrease in Eb, whereas the maximal reduction is 27% for thick hBN. We have performed similar calculations in the case of a WSe2 monolayer deposited on stacked hBN layers. These results are compared to the recently proposed quantum electrostatic heterostructure approach.
关键词： GW wave functions,density functional theory,hexagonal-boron nitride,two-dimensional transition-metal dichalcogenide,Bethe-Salpeter equation,exciton
更新于2025-09-04 15:30:14
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2-Level Quantum Systems in 2-D Materials for Single Photon Emission
摘要： Single photon emission (SPE) by a solid state source requires presence of a distinct two-level quantum system, usually provided by point defects. Here we note that a number of qualities offered by novel, two dimensional materials—their all-surface openness and optical transparence, tighter quantum confinement, and reduced charge screening—are advantageous for achieving an ideal SPE. Based on first principles calculations and point-group symmetry analysis, a strategy is proposed to design paramagnetic defect complex with reduced symmetry, meeting all the requirements for SPE: its electronic states are well isolated from the host material bands, belong to a majority spin eigenstate, and can be controllably excited by polarized light. The defect complex is thermodynamically stable, and appears feasible for experimental realization, to serve as a SPE-source, essential for quantum computing, with ReMoVS in MoS2 as one most practical candidate.
关键词： diamane,boron nitride,ab initio,Photonic qubits,color centers,paramagnetic defects,transition metal dichalcogenides
更新于2025-09-04 15:30:14