Atomic-Scale Structural and Chemical Characterization of Hexagonal Boron Nitride Layers Synthesized at the Wafer-Scale with Monolayer Thickness Control

Lin, Wei Hsiang; Brar, Victor W.; Jariwala, Deep; Sherrott, Michelle C.; Tseng, W. F.; Wu, Chih I.; Yeh, N.-C.; Atwater, Harry A.

doi:10.1021/acs.chemmater.7b00183

Cited by 38 publications

(33 citation statements)

References 42 publications

(61 reference statements)

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“…The E 2g modes were fit with a Lorentzian, giving full‐width at half maximum of 24.35 cm −1 for the standard grown hBN, which decreases to 17.60 and 15.90 cm −1 for preoxidized and gettering growth conditions, respectively (Figure S7, Supporting Information). This confirms the superior crystallinity of hBN grown films by the gettering method . The increasing crystallinity can be ascribed to modification of the Cu catalyst during gettering growth, which slows nucleation and growth kinetics, and reduces the effects of lattice constant changes, and high defect density growth during cooling by boron precipitation from the catalyst .…”

Section: Comparison Of Emission Energy and Density Of Cvd Hbn Spes Insupporting

confidence: 56%

Selective Defect Formation in Hexagonal Boron Nitride

Abidi

Mendelson

Tran

et al. 2019

Advanced Optical Materials

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Robust and photostable single photon emitters (SPEs) underpin a number of promising quantum information science and technologies. [1][2][3][4] Solid-state quantum light sources are highly sought after for their ease of integration into onchip architectures, and rapid progress has been made recently with a variety of solidstate sources such as quantum dots, [5,6] color centers in diamond, [7,8] silicon carbide, [9,10] rare-earth materials, [11] carbon nanotubes, [12] and layered van der Waals materials. [3] One of the most promising candidates are quantum emitters in hexagonal boron nitride (hBN), which have recently emerged as a robust solid-state platform capable of hosting bright, [13][14][15][16][17] linearly polarized, [13,18] and optically stable SPEs operating at room temperature with high photon purity. [19,20] While the zerophonon lines (ZPLs) of hBN quantum emitters have been known to display a wide spread of energies (≈1.6-2.4 eV), implying the existence of multiple defect species, [15,18,[21][22][23] recent progress utilizing chemical vapor deposition (CVD) has shown that this spread can be reduced to ≈100 meV. [24,25] This reduced ZPL energy distribution is useful both for applications and for basic studies of the defects responsible for the emissions. However, to fully understand and exploit the diversity of emissions reported in hBN further advances in controlling the observed emission spectra and emitter density are required.In order to target the incorporation of particular structural defects during CVD growth, a method to modify the dominant defect formation processes is required. In situ monitoring of hBN growth on Cu has clarified that hBN growth is subject to complex interaction between the precursor species, and the catalyst surface/bulk. [26] As a result, controlling the interactions between the precursor species and the catalyst is critical to achieve highly crystalline hBN growth, but also offers a promising avenue to controlled defect engineering during CVD growth of hBN. In other material systems such as InAs/ GaAs quantum dots modifying catalyst properties such as lattice mismatch during epitaxial growth has been definitively linked to defect creation. [27] Similarly graphene is known to be dependent of the interactions with the catalyst bulk/surface, where growth depends strongly on the relative phase of the catalyst and the supply of carbon in and out of the catalyst, controlling both defect formation and density. [28,29] Despite added complications for CVD growth of hBN, especially due to Luminescent defects in hexagonal boron nitride (hBN) have emerged as promising single photon emitters (SPEs) due to their high brightness and robust operation at room temperature. The ability to create such emitters with well-defined optical properties is a cornerstone toward their integration into on-chip photonic architectures. Here, an effective approach is reported to fabricate hBN SPEs with desired emission properties in distinct spectral regions via the manipulation of boron diffusion through ...

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Section: Comparison Of Emission Energy and Density Of Cvd Hbn Spes Insupporting

confidence: 56%

Selective Defect Formation in Hexagonal Boron Nitride

Abidi

Mendelson

Tran

et al. 2019

Advanced Optical Materials

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“…Spectroscopic Characterizations. Raman scattering is known to be a sensitive tool to detect the disorder induced by impurities and defects, which have been demonstrated to be very effective in studying graphene-like materials (55,56). The Raman spectra are presented in Fig.…”

Section: Resultsmentioning

confidence: 99%

Enhanced and stabilized hydrogen production from methanol by ultrasmall Ni nanoclusters immobilized on defect-rich h-BN nanosheets

Zhang

Sanz-Matı́as

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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Employing liquid organic hydrogen carriers (LOHCs) to transport hydrogen to where it can be utilized relies on methods of efficient chemical dehydrogenation to access this fuel. Therefore, developing effective strategies to optimize the catalytic performance of cheap transition metal-based catalysts in terms of activity and stability for dehydrogenation of LOHCs is a critical challenge. Here, we report the design and synthesis of ultrasmall nickel nanoclusters (∼1.5 nm) deposited on defect-rich boron nitride (BN) nanosheet (Ni/BN) catalysts with higher methanol dehydrogenation activity and selectivity, and greater stability than that of some other transition-metal based catalysts. The interface of the two-dimensional (2D) BN with the metal nanoparticles plays a strong role both in guiding the nucleation and growth of the catalytically active ultrasmall Ni nanoclusters, and further in stabilizing these nanoscale Ni catalysts against poisoning by interactions with the BN substrate. We provide detailed spectroscopy characterizations and density functional theory (DFT) calculations to reveal the origin of the high productivity, high selectivity, and high durability exhibited with the Ni/BN nanocatalyst and elucidate its correlation with nanocluster size and support–nanocluster interactions. This study provides insight into the role that the support material can have both regarding the size control of nanoclusters through immobilization during the nanocluster formation and also during the active catalytic process; this twofold set of insights is significant in advancing the understanding the bottom-up design of high-performance, durable catalytic systems for various catalysis needs.

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“…To test the effect of measurement environment and h-BN crystal morphology on inhomogeneous broadening we transfer 5-nm-thick CVD-grown h-BN films from the copper growth substrate onto SiO 2 and ITO substrates using wet-transfer techniques (for details about the growth method, see Ref. [51] and the Supplemental Material [41]). We also exfoliate a 5-nm-thick h-BN onto SiO 2 substrate and an 8-nm-thick h-BN onto the ITO substrate.…”

Section: B Low-temperature Broadening and The Substrate Effectsmentioning

confidence: 99%

Temperature-dependent Spectral Emission of Hexagonal Boron Nitride Quantum Emitters on Conductive and Dielectric Substrates

et al. 2021

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We report a reduction in the linewidth and suppression of spectral diffusion of quantum emitters in hexagonal boron nitride supported on a conductive substrate. We observe a temperature-dependent reduction in the spectral emission linewidth for CVD-grown and exfoliated crystals on conductive ITO relative to those seen on silicon dioxide (SiO 2 ) substrates. We show that the inhomogeneous linewidth can be suppressed by 45% as a result of using a conductive substrate. We investigate the zero-phonon line profile at temperatures ranging from 4 to 300 K and decompose the effects of thermal broadening and spectral diffusion at each temperature by Voigt fitting. The temperature dependence of homogeneous and inhomogeneous components of the broadening is discussed.

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Atomic-Scale Structural and Chemical Characterization of Hexagonal Boron Nitride Layers Synthesized at the Wafer-Scale with Monolayer Thickness Control

Abstract: Hexagonal boron nitride (h-BN) is a promising two-dimensional insulator with a large band gap and low density of charged impurities that is isostructural and isoelectronic with graphene. Here we report the chemical and atomic-scale structure of CVD-grown wafer-scale (~25 cm 2 ) h-BN sheets

Cited by 38 publications

References 42 publications

Selective Defect Formation in Hexagonal Boron Nitride

Selective Defect Formation in Hexagonal Boron Nitride

Enhanced and stabilized hydrogen production from methanol by ultrasmall Ni nanoclusters immobilized on defect-rich h-BN nanosheets

Temperature-dependent Spectral Emission of Hexagonal Boron Nitride Quantum Emitters on Conductive and Dielectric Substrates

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