Effect of the seed layer crystalline structure in the growth of zinc-tin oxide (ZTO) nanostructures

Metal oxide nanostructures have recently gained high attention due to advances in their synthesis, particularly hydrothermal techniques, which allow precise control over their morphology, composition, and crystallinity, as well as integration into devices. Zinc-tin oxide (ZTO) nanostructures, in particular, are notable for their sustainability and multifunctional applications, including catalysis, electronics, sensors, and energy harvesting. Their ternary oxide nature supports a broad range of functionalities. The use of seed layers during synthesis has proven to be beneficial, particularly for binary systems such as ZnO, as it not only impacts the growth of nanostructures but is also advantageous for applications requiring nanostructures supported on substrates, such as in photocatalysis and sensor technologies. This work investigates the effect of various seed layers (e.g., Cu, stainless steel, Cr, Ni) on the hydrothermal synthesis of ZTO nanostructures. Compared to seed layer free methods under similar conditions, the presence of seed layers significantly influenced the resulting structures. The study produced diverse morphologies, including ZnSnO₃ nanowires and Zn₂SnO₄ nanoparticles, octahedrons, and nanowires. Findings suggest a relationship between the seed layer's phase and the resulting nanostructure phase. Furthermore, shorter synthesis durations favored discrete nanostructures, while longer durations facilitated the formation of thin films with nanostructured surfaces. These observations underscore the dual role of seed layers in influencing both the structural phase and growth kinetics of ZTO nanostructures.