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

Abstract

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.

Direct growth of hexagonal boron nitride on non-metallic substrates and its heterostructures with graphene

“…The h-BN films are formed on substrates whose thermocouple temperatures are high enough to enable nucleation of boron from its source and active nitrogen flowing at a precise flow rate and pressure. Both transmission electron microscopy (TEM) and Scanning TEM (STEM) ( Figures 3 C–1) prove that the smoother, layered sample formed through crystal nucleation or competitive growth and decomposition (resulting in slow growth rates) is of high quality ( Page et al., 2019 ). The Raman (532 nm laser) peaks ( Figures 3 C–2, right-bottom) for both grown samples were consistent at 1363 cm −1 , with the smooth, layered sample producing sharper peaks, while the rough, polycrystalline sample produced broader, and more intense peaks ( Page et al., 2019 ).…”

“…Recently, attempts have been made to directly grow h-BN sheets on insulating/dielectric substrates like SiO 2 /Si, Si 3 N 4 /Si, silicon (111), quartz, sapphire, single crystal diamond, and 6H-SiC by employing techniques such as: low-pressure thermal chemical vapor deposition (CVD) ( Behura et al., 2015 , 2017 ; Jang et al., 2016 ; Pendse et al., 2021 ; Tay et al., 2015 ; Wang et al., 2020 ), cold wall chemical vapor deposition ( Ahmed et al., 2016 ), metal organic chemical vapor deposition (MOCVD) ( Majety et al., 2013 ; Vangala et al., 2018 ), molecular beam epitaxy (MBE) ( Page et al., 2019 ) ( Vuong et al., 2017 ), ion beam sputtering deposition (IBSD) ( Gao et al., 2019 ), metal organic vapor phase epitaxy (MOVPE) ( Chugh et al., 2018 ; Yang et al., 2018 , 2020 ), and atomic layer deposition (ALD) ( Lee et al., 2020 ; Park et al., 2017 ). Here we sift through some key techniques and related mechanistic principles to nucleate h-BN crystals on dielectric substrates.…”

“…The C-2 presents the Raman spectroscopic results with E 2g vibrational mode at 1363 cm −1 with FWHM of 14.1 cm −1 ). Reprinted with permission from ( Page et al., 2019 ). …”

Boron nitride for excitonics, nano photonics, and quantum technologies

“…There are currently a lot of worldwide attempts among which are the pioneering works in the groups of H.X. Jiang at Austin (MOCVD) [37], S.V.Novikov at Nottingham (MBE) [38] and D. Jena at Cornell [39]. Epitaxial hBN can be grown with different thicknesses from the monolayer (MLBN) to very thick stacking.…”

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

“…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].…”