Hexagonal Boron Nitride Single Crystal Growth at Atmospheric Pressure Using Ni−Cr Solvent

Abstract

Hexagonal boron nitride (hBN), with a layered structure similar to that of graphite, is the simplest III-V nitride compound. High-purity hBN emits intense 215-nm bandedge luminescence, which is attributed to free excitons and which may have potential wide band gap semiconductor characteristics. 1 It is a promising material for the production of deep ultraviolet light-emitting devices. However, the synthesis routes for high-purity hBN single crystal have thus far all been high-pressure, high-temperature (HP-HT) ones. [1][2][3] Since products of HP-HT synthesis are generally limited in size, development of an alternative synthesis process that can fabricate hBN fine crystal on a large scale is an important step in realizing hBN's potential.We recently found a new way of obtaining hBN crystals at atmospheric pressure using Ni-Mo alloy as a solvent. 4 The obtained crystals exhibit the band-edge optical nature of deep ultraviolet luminescence at 215 nm at room temperature, which indicates high crystallinity of our crystals.

Optimization of Ni–Cr flux growth for hexagonal boron nitride single crystals

“…Solvent choices that have been tested for hBN crystal growth have included silicon [12], sodium [13], lithium bromide (LiBr) [14], copper [15], and BaF 2 -Li 3 N [16]. The process employing a nickel-chromium flux developed by Kubota et al [17] has perhaps been the most successful in its ability to produce good sized crystals (>500 µm) at modest temperature (1500 °C) with excellent optical properties. For this reason, the Ni-Cr flux growth method was employed in this study.…”

Characterization of bulk hexagonal boron nitride single crystals grown by the metal flux technique

“…There have been relatively few studies on the bulk crystal growth of hBN [10][11][12][13][14]. These employed a variety of solvents for hBN including silicon [10], copper [11], sodium [12], and nickel-chromium [13,14].…”

“…These employed a variety of solvents for hBN including silicon [10], copper [11], sodium [12], and nickel-chromium [13,14]. Here we adapt the method developed by Kubota et al [14] employing a Ni-Cr flux, due to its relatively modest temperature, ability to achieve reasonably fast growth rates, and ability to produce crystals at atmospheric pressure.…”

Point defects in hexagonal BN, BC3 and BCxN compounds studied by x-ray absorption near-edge structure

“…3,13 Highly oriented polycrystalline h-BN bulk samples are also obtained by compressionannealed pyrolysis. 14 Furthermore, CVD [15][16][17][18][19][20] and PVD 10,15,[21][22][23][24][25][26] techniques have been extensively employed to grow h-BN thin films with different degrees of structural disorder.…”