Zinc oxide (ZnO) nanorods exhibit unique anisotropic growth behaviour influenced by surface energy variations, chemical potential gradients, and synthesis conditions. This study explores the fundamental thermodynamic and kinetic factors governing ZnO nanorod formation, focusing on surface energy minimization, Gibbs free energy stability, and Wulff construction-based morphology prediction. The role of chemical potential, supersaturation, and Ostwald ripening in directing anisotropic growth along the c-axis is also analyzed. Additionally, the hydrothermal synthesis of ZnO nanorods, the most often used synthesis process has also been used an example for understanding the whole ZnO nanorod formation process, highlighting the impact of reaction parameters such as temperature, pH, precursor concentration, and surfactant-mediated morphology control.

Keywords: ZnO Nanorod; Surface Energy; Wulff Construction Method;