In Situ Microbeam Surface X-ray Scattering Reveals Alternating Step Kinetics During Crystal Growth
| Autor: | Ju, Guangxu, Xu, Dongwei, Thompson, Carol, Highland, Matthew J., Eastman, Jeffrey A., Walkosz, Weronika, Zapol, Peter, Stephenson, G. Brian |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Nat Commun 12, 1721 (2021) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1038/s41467-021-21927-5 |
| Popis: | The stacking sequence of hexagonal close-packed and related crystals typically results in steps on vicinal {0001} surfaces that have alternating A and B structures with different growth kinetics. However, because it is difficult to experimentally identify which step has the A or B structure, it has not been possible to determine which has faster adatom attachment kinetics. Here we show that in situ microbeam surface X-ray scattering can determine whether A or B steps have faster kinetics under specific growth conditions. We demonstrate this for organo-metallic vapor phase epitaxy of (0001) GaN. X-ray measurements performed during growth find that the average width of terraces above A steps increases with growth rate, indicating that attachment rate constants are higher for A steps, in contrast to most predictions. Our results have direct implications for understanding the atomic-scale mechanisms of GaN growth and can be applied to a wide variety of related crystals. Comment: Main paper: 11 pages, 8 figures; Supplemental: 8 pages, 12 figures. Version 3 is similar to v2, with additional edits to text and figures for clarity. In-depth descriptions of BCF (growth) model extended to alternating steps and CTR (scattering) analysis can be found at arXiv:2010.09575 and arXiv:2010.06166 (admin note: substantial text overlap with arXiv:2007.05083) |
| Databáze: | arXiv |
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