High-Temperature Molecular Beam Epitaxy of Hexagonal Boron Nitride with High Active Nitrogen Fluxes

Cheng, T.S.; Summerfield, Alex; Mellor, Christopher J.; Khlobystov, Andrei N.; Eaves, L.; Foxon, C.T.; Beton, Peter H.; Новиков, С. В.

doi:10.3390/ma11071119

Cited by 21 publications

(14 citation statements)

References 41 publications

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“…More details about the sample growth conditions and the MBE system can be found elsewhere. 53,[120][121][122] STM/STS STM and STS measurements were performed under ultra-high vacuum (UHV) conditions at low-temperatures using a modified RHK PanScan FlowCryo microscope. This STM was adapted to receive a high numerical aperture light collection and injection system with optimized transmission.…”

Section: Methods Sample Preparationsmentioning

confidence: 99%

Band gap measurements of monolayer h-BN and insights into carbon-related point defects

Román¹,

Costa²,

Zobelli³

et al. 2021

2D Mater.

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Being a flexible wide band gap semiconductor, hexagonal boron nitride (h-BN) has great potential for technological applications like efficient deep ultraviolet (DUV) light sources, building block for two-dimensional heterostructures and room temperature single photon emitters in the UV and visible spectral range. To enable such applications, it is mandatory to reach a better understanding of the electronic and optical properties of h-BN and the impact of various structural defects. Despite the large efforts in the last years, aspects such as the electronic band gap value, the exciton binding energy and the effect of point defects remained elusive, particularly when considering a single monolayer.Here, we directly measured the density of states of a single monolayer of h-BN epitaxially grown on highly oriented pyrolytic graphite, by performing low temperature scanning tunneling microscopy (LT-STM) and spectroscopy (STS). The observed h-BN electronic band gap on defect-free regions is (6.8 ± 0.2) eV. Using optical spectroscopy to obtain the h-BN optical band gap, the exciton binding energy is determined as being of (0.7 ± 0.2) eV. In addition, the locally excited cathodoluminescence and photoluminescence show complex spectra that are typically associated to intragap states related to carbon defects. Moreover, in some regions of the monolayer h-BN we identify, using STM, point defects which have intragap electronic levels around 2.0 eV below the Fermi level.

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Section: Methods Sample Preparationsmentioning

confidence: 99%

Band gap measurements of monolayer h-BN and insights into carbon-related point defects

Román¹,

Costa²,

Zobelli³

et al. 2021

2D Mater.

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“…Unlike the MBE growth of wurtzite III-nitrides, which demonstrate smooth, epitaxial growth under metal-rich flux ratios, optimal growth conditions for hBN are under an excess of active nitrogen. While a recent report suggests an influence of active N flux on hBN morphology on HOPG, the ratelimiting element, boron, will govern the overall morphology and growth rate of these films [29]. Therefore, in this work, the nitrogen flux was kept constant while the boron flux and the substrate temperature were varied.…”

Section: Methodsmentioning

confidence: 99%

Rotationally aligned hexagonal boron nitride on sapphire by high-temperature molecular beam epitaxy

Page

Casamento

Cho

et al. 2019

Phys. Rev. Materials

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Hexagonal boron nitride (hBN) has been grown on sapphire substrates by ultrahigh-temperature molecular beam epitaxy (MBE). A wide range of substrate temperatures and boron fluxes have been explored, revealing that high crystalline quality hBN layers are grown at high substrate temperatures, >1600℃ , and low boron fluxes, ∼1 × 10 %& Torr beam equivalent pressure. In situ reflection high-energy electron diffraction revealed the growth of hBN layers with 60° rotational symmetry and the [112 + 0] axis of hBN parallel to the [11 + 00] axis of the sapphire substrate. Unlike the rough, polycrystalline films previously reported, atomic force microscopy and transmission electron microscopy characterization of these films demonstrate smooth, layered, few-nanometer hBN films on a nitridated sapphire substrate. This demonstration of high-quality hBN growth by MBE is a step toward its integration into existing epitaxial growth platforms, applications, and technologies.

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“…Among them, PA-MBE has an exact growth control to produce high-quality epitaxy and at lower growth temperatures than others [12,13]. h-BN has also attracted attention for the growth on various substrates, such as Ni [10,14], graphene [15,16], cobalt [17,18], and sapphire [19,20].…”

Section: Introductionmentioning

confidence: 99%

The Growth of Hexagonal Boron Nitride Quantum Dots on Polycrystalline Nickel Films by Plasma-Assisted Molecular Beam Epitaxy

et al. 2022

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In this report, quantum dots of hexagonal boron nitride (h-BN) were fabricated on the surface of polycrystalline Ni film at low growth temperatures (700, 750, and 800 °C) by plasma-assisted molecular beam epitaxy. Reflection high-energy electron diffraction could trace the surface condition during the growth and perform the formation of BN. The observation of surface morphology by scanning electron microscopy and atomic force microscopy showed the nanodots of BN on Ni films. The existence of crystal h-BN quantum dots was determined by the analysis of Raman spectra and Kevin probe force microscopy. The cathodoluminescence of h-BN quantum dots performed at the wavelength of 546 and 610 nm, attributed to the trapping centers involving impurities and vacancies. Moreover, the influence of temperatures for the substrate and boron source cell was also investigated in the report. When the k-cell temperature of boron and growth temperature of substrate increased, the emission intensity of cathodoluminescence spectra increased, indicating the better growth parameters for h-BN quantum dots.

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High-Temperature Molecular Beam Epitaxy of Hexagonal Boron Nitride with High Active Nitrogen Fluxes

Cited by 21 publications

References 41 publications

Band gap measurements of monolayer h-BN and insights into carbon-related point defects

Band gap measurements of monolayer h-BN and insights into carbon-related point defects

Rotationally aligned hexagonal boron nitride on sapphire by high-temperature molecular beam epitaxy

The Growth of Hexagonal Boron Nitride Quantum Dots on Polycrystalline Nickel Films by Plasma-Assisted Molecular Beam Epitaxy

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