Tuning formation process of void defects in microcolumn arrays via pulse reverse electrodeposition

The pulse reverse current electrodeposition process consists of two stages: the forward deposition and reverse dissolution. This study aims to understand the characteristics of forward deposition and reverse dissolution and to reveal their influences on the formation of void defects in electrodeposited microcolumn arrays. Both the simulation and experimental results show that pulse reverse current contributes to the void-free deposition of micro -column arrays. During the deposition under forward pulse stage, the thickness of deposited layer in micro cavities via pulse reverse current is more uniform compared with direct current. Meanwhile, the dissolution behavior under reverse pulse stage is greatly determined by the reverse pulse current density. A low reverse pulse current density (1 A/dm2) leads to a slow dissolution at the mouth of micro cavities. In contrast, a high reverse pulse current density (4 A/dm2) contributes to a high electrolyte potential, as well as a rapid dissolution at the mouth of micro cavities, which helps to eliminate void defects. The experimental results exhibit that void-free microcolumn arrays with a high aspect ratio of 5:1 are obtained via pulse reverse current. This study provides a clear understanding on the formation process of void defects in microcolumn arrays via pulse reverse electrodeposition.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).