In situ microbeam surface X-ray scattering reveals alternating step kinetics during crystal growth.

Autor: Ju G; Materials Science Division, Argonne National Laboratory, Lemont, IL, USA. juguangxu@gmail.com.; Lumileds Lighting Co., San Jose, CA, USA. juguangxu@gmail.com., Xu D; Materials Science Division, Argonne National Laboratory, Lemont, IL, USA.; School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, China., Thompson C; Department of Physics, Northern Illinois University, DeKalb, IL, USA., Highland MJ; X-ray Science Division, Argonne National Laboratory, Lemont, IL, USA., Eastman JA; Materials Science Division, Argonne National Laboratory, Lemont, IL, USA., Walkosz W; Department of Physics, Lake Forest College, Lake Forest, IL, USA., Zapol P; Materials Science Division, Argonne National Laboratory, Lemont, IL, USA., Stephenson GB; Materials Science Division, Argonne National Laboratory, Lemont, IL, USA. stephenson@anl.gov.
Jazyk: angličtina
Zdroj: Nature communications [Nat Commun] 2021 Mar 19; Vol. 12 (1), pp. 1721. Date of Electronic Publication: 2021 Mar 19.
DOI: 10.1038/s41467-021-21927-5
Abstrakt: 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.
Databáze: MEDLINE
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