Understanding surface dynamics during epitaxial film growth is key to growing high quality materials with controllable properties. X-ray photon correlation spectroscopy (XPCS) using coherent x-rays opens new opportunities for in situ observation of atomic-scale fluctuation dynamics during crystal growth. Here, we present the first XPCS measurements of 2D island dynamics during homoepitaxial growth in the layer-by-layer mode. Analysis of the results using two-time correlations reveals a new phenomenon - a memory effect in island nucleation sites on successive crystal layers. Simulations indicate that this persistence in the island arrangements arises from communication between islands on different layers via adatoms. With the worldwide advent of new coherent x-ray sources, the XPCS methods pioneered here will be widely applicable to atomic-scale processes on surfaces.
@article{arxiv.1804.08161,
title = {Persistence of Island Arrangements During Layer-by-Layer Growth Revealed Using Coherent X-rays},
author = {Guangxu Ju and Dongwei Xu and Matthew J. Highland and Carol Thompson and Hua Zhou and Jeffrey A. Eastman and Paul H. Fuoss and Peter Zapol and Hyunjung Kim and G. Brian Stephenson},
journal= {arXiv preprint arXiv:1804.08161},
year = {2020}
}
Comments
13 page, 5 figures, also note additional supplementary document of 10 pages, 7 figures