On the growth morphology of hard gold electrodeposits

Abstract

“Rounded mound” growth structures are found to form under a wide variety of deposition conditions, including electrodeposition, sputtering, and vapor deposition. In this study, the rounded mound structure of a specific system, hard gold electrodeposits, was investigated using scanning and transmission electron microscopes in order to explore the relationship between the growth morphology and the structure of the deposits. It was found that the rounded mounds consist of extremely fine ( ∽ 200 Å)gold grains, the nucleations of which were accompanied by the incorporation of numerous nonmetallic molecules. Electron diffraction patterns from both the horizontal and cross sections of the rounded mounds revealed that the perimeter of the rounded mounds containing the fine grains was bounded preferentially by the {111} cross-packed planes. It was shown that the formation of the rounded mound structure is promoted by the continuous adsorption and subsequent incorporation of nonmetallic molecules, which act as growth inhibitors.