Controlling ZnO Nanorods Morphology by Seeded Layer Assisted Chemical Vapor Deposition

Vertically aligned zinc oxide (ZnO) nanorods (NRs) were grown using a seeded layer-assisted chemical vapor deposition technique. This study examined the impact of altered evaporation crucible-substrate spacing (3, 4, 5, and 6 cm) on the optical behavior, morphological characteristics, and elemental composition of ZnO thin films prepared as a seed layer (buffer layer). Besides, the surface morphology and structural characteristics of the synthesized ZnO NRs was evaluated in the presence and absence of the seed layer. Seed layer samples were evaluated by an ultraviolet-visible spectrophotometer, a field emission scanning electron microscope (FESEM), and energy-dispersive X-ray (EDX) spectroscopy. In contrast, the NRs samples were characterized using FESEM and X-ray diffraction (XRD) technique. The optical energy gap results showed a blue shift from 3.23 eV to 3.28 eV as the separation spacing increased from 3 cm to 6 cm, respectively. FESEM images revealed that the separation spacing strongly influences the morphology of the ZnO films. EDX analysis of the seed layer disclosed the presence of prominent peaks for zinc and oxygen, which confirmed the elemental composition of the grown samples. Furthermore, ZnO NRs synthesized in the absence of a seed layer were observed to be shorter, misaligned, exhibit random growth rates, and possess inferior quality compared to those synthesized with a seed layer. XRD analysis confirmed the high crystalline quality of the grown nanorod samples. Our systematic technique for the synthesis and characterization of the seed layer could play a significant role in the production of superior nanorod arrays.