Fundamentals of Au(111) Surface Dynamics: Coarsening of Two-Dimensional Au Islands

• Published in: Journal of physical chemistry. C Vol. 124; no. 13; pp. 7492 - 7499
• Main Authors: Spurgeon, Peter M, Lai, King C, Han, Yong, Evans, James W, Thiel, Patricia A
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 02-04-2020
• Subjects: diffusion; energy; gold; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; metals; scanning tunneling microscopy
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.9b12056

Au­(111) surfaces play a central role in many applications, yet studies of fundamental aspects of their dynamics are limited. Thus, using scanning tunneling microscopy (STM) at 300 K, we analyze the coarsening of first-layer 2D Au islands directly on the Au(111) substrate and also of second-layer 2D Au islands. Specifically, we monitor the decay of Au first-layer islands with areas of about 100–500 nm2 in the vicinity of larger islands or extended step edges over a period of approximately 40 h, the relevant time scale for this process. Experimentally observed behavior is captured by analytical theory for terrace-diffusion-limited decay incorporating DFT results for the Au terrace diffusion barrier and the adatom formation energy. Experimental observations of second-layer island decay are also compared with appropriate analytical theory and stochastic simulations, thereby determining the effective Ehrlich–Schwoebel barrier for Au on Au(111).