In Situ Microbeam Surface X-ray Scattering Reveals Alternating Step Kinetics During Crystal Growth
Abstract
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.
Keywords
Cite
@article{arxiv.2007.05090,
title = {In Situ Microbeam Surface X-ray Scattering Reveals Alternating Step Kinetics During Crystal Growth},
author = {Guangxu Ju and Dongwei Xu and Carol Thompson and Matthew J. Highland and Jeffrey A. Eastman and Weronika Walkosz and Peter Zapol and G. Brian Stephenson},
journal= {arXiv preprint arXiv:2007.05090},
year = {2021}
}
Comments
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)