Epitaxial Combination of Two-Dimensional Hexagonal Boron Nitride with Single-Crystalline Diamond Substrate

Abstract

Hexagonal boron nitride (hBN) and diamond are promising materials for next-generation electronics and optoelectronics. However, their combination is rarely reported. In this study, we for the first time demonstrate the success to direct growth of two-dimensional (2D) hBN crystal layers on diamond substrates by metalorganic vapor phase epitaxy. Compared with the disordered growth we found on diamond (100), atomic force microscopy, X-ray diffraction, and transmission electron microscopy results all support 2D hBN with highly oriented lattice formation on diamond (111). Also, the epitaxial relationship between hBN and diamond (111) substrate is revealed to be [0 0 0 1] hBN // [1 1 1] diamond and [1 0 1̅ 0] hBN // [1 1 2̅ ] diamond . The valence band offset at hBN/diamond (111) heterointerface determined by X-ray photoelectron spectroscopy is 1.4 ± 0.2 eV, thus yielding a conduction band offset of 1.0 ± 0.2 eV and type II staggered band alignment with a bandgap of 5.9 eV assumed for hBN. Furthermore, prior thermal cleaning of diamond in a pure H 2 atmosphere smoothens the surface for well-ordered layered hBN epitaxy, while thermal cleaning in a mixed H 2 and NH 3 atmosphere etches the diamond surface, creating many small faceted pits that destroy the following epitaxy of hBN.

Ab initio study of the effect of 2D layer rippling on the electronic properties of 2D/H-terminated diamond (100) heterostructures

“…This 23% reduction in the VBE energy of the constituent layer as a result of rippling is an indication of a stronger interaction between the wavy layer and the H-diamond (100) surface, confirmed by the larger vdW energy and charge transfer in this system. Both heterostructures show a Type-II band alignment where CB edge of the hBN is below (above) the CB (VB) edge of the H-diamond (100) surface, which is consistent with the band alignment feature extracted by the XPS method in a recent experimental study [48].…”

Structure, Properties and Applications of Two‐Dimensional Hexagonal Boron Nitride

“…This predicted band alignment is validated in a recent experimental work. [ 389 ] The spatially separated electrons and holes are tightly bound and long‐lived and form indirect excitons. These intriguing electrical neutral quasiparticles are of considerable interest in current research on next‐generation electronic and optical devices.…”

“…A recent report by Yang et al describes a disordered growth of h-BN on diamond (100) and highly oriented growth on diamond (111) by means of metalorganic vapor phase epitaxy at 1380 °C. [389] However, in a first principle calculation of hydrogen diffusion through an h-BN/diamond heterointerface, diffusion potential barrier of ≈10 eV are calculated that is an order of magnitude higher than that encountered in the graphene/diamond heterointerface, rendering it experimentally impracticable to achieve hydrogenation through h-BN layer in h-BN/diamond heterostructure.…”

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

“…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.…”