Exploring the Mechanisms Driving Thermal Growth of Copper Oxide Nanowires

Abstract

Copper oxide nanowires have gained attention in the scientific community due to their potential in a wide range of applications, including gas sensing, solar cells, energy storage, photocatalysis, and as antibacterial agents. Despite significant research on their thermal growth, the underlying mechanism remains unresolved, and the exact experimental conditions required for their growth are still unknown. To address these knowledge gaps, we conducted thermal oxidation of copper under various conditions and analyzed the resulting nanowires using electron microscopy techniques. Our study aimed to understand the processes occurring inside the copper oxide layers, which serve as the starting point for nanowire growth, as well as the driving force behind the one-dimensional growth of nanowires. Additionally, we explored the effects of experimental conditions on the microstructure of the copper oxide layers and nanowires. Our findings indicate that chemical processes inside the oxide layers are influenced by copper and oxygen concentration gradients, with oxygen concentration being the key factor in determining the prevalent copper oxide phase. Moreover, the microstructure of both the oxide layers and nanowires is affected by stress and defects in the oxide layers. We found that twin boundaries in the CuO grains are the main reason for the unidirectional elongation of nanowires. Our research provides important insights into the mechanisms driving the thermal growth of copper oxide nanowires, which can aid in their synthesis and applications in various fields.