Growth of hexagonal BN crystals by traveling-solvent floating zone
| Autor: | Zoghlin, Eli, Plo, Juliette, Ye, Gaihua, Nnokwe, Cynthia, Gomez, Reina, Ferrenti, Austin, Kushwaha, Satya, He, Rui, Wilson, Stephen D., Valvin, Pierre, Gil, Bernard, Cassabois, Guillaume, Edgar, James H., McQueen, Tyrel M. |
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| Rok vydání: | 2024 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | Large, high-purity single-crystals of hexagonal BN (h-BN) are essential for exploiting its many desirable and interesting properties. Here, we demonstrate via X-ray tomography, X-ray diffraction and scanning electron microscopy that h-BN crystals can be grown by traveling-solvent floating-zone (TSFZ). The diameters of grown boules range from 3 -- 5 mm with lengths from 2 -- 7 mm. Tomography indicates variable grain sizes within the boules, with the largest having areas of $\approx$ 1 mm $\times$ 2 mm and thickness $\approx$ 0.5 mm. Although the boules contain macroscale flux inclusions, the h-BN lattice itself is of high quality for samples grown under optimized conditions. The currently optimized growth procedure employs an Fe flux, moderate N$_2$ pressure ($P_{N2} \approx$ 6 bar), and a growth rate of 0.1 mm/h.Raman spectroscopy for an optimized sample gives an average linewidth of 7.7(2) cm$^{-1}$ for the $E_{2g}$ intralayer mode at 1365.46(4) cm$^{-1}$ and 1.0(1) cm$^{-1}$ for the $E_{2g}$ interlayer shear mode at 51.78(9) cm$^{-1}$. The corresponding photoluminescence spectrum shows sharp phonon-assisted free exciton peaks and minimal signal in the energy range corresponding to carbon-related defects ($E$ = 3.9 -- 4.1 eV). Our work demonstrates the viability of growing h-BN by the TSFZ technique, thereby opening a new route towards larger, high-quality crystals and advancing the state of h-BN related research. Comment: 12 pages, 6 figures + supplementary information. Submitted to J. Cryst. Growth |
| Databáze: | arXiv |
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