Fabrication of Highly Uniform, Well‐Aligned ZnO Nanorod Arrays via Hydrothermal Synthesis for RGB Micro‐ and Submicron‐Scale LEDs

NanoLEDs are increasingly in demand for high-resolution displays and localized illumination in advanced sensing and imaging. This study proposes an improved hydrothermal synthesis process for fabricating uniform, refined ZnO nanorods that maintain their uniformity in high-density arrays. By inducing convection flow and comparatively low temperature environment in the synthesis process, a persistent supply of reactive agents and controlled growth conditions are achieved, enhancing nanorod uniformity. Compared to non-convection growth, the standard deviations of height and diameter are reduced by 63.2% and 67.3%, respectively. Structural parameters such as nanorod pitch and diameter of nucleation sites are investigated to optimize uniform growth. Furthermore, the stable LED operation and RGB emission of the synthesized ZnO nanorods are demonstrated. The vivid RGB emission from precisely structured ZnO nanorods confirms their potential for full-color nanopixel displays and advanced nanophotonic applications.