Catalyst-free large-quantity synthesis of ZnO nanorods by a vapor-solid growth mechanism: Structural and optical properties

The formation of high-density ZnO nanorods has been achieved by a vapor-solid growth mechanism using metallic zinc powder and oxygen gas as source materials for zinc and oxygen, respectively. General morphological studies indicated that the as-grown products are flower-shaped containing several hundreds of nanorods. The obtained nanorods have a diameter of 150-250 nm while their lengths are 5-10 μm. The detailed structural analysis revealed that the ZnO nanorods exhibit a single crystalline wurtzite hexagonal structure and preferentially oriented in the c-axis direction. Room temperature Raman scattering and photoluminescence studies found that the as-grown ZnO nanorods have good crystal quality with the hexagonal wurtzite phase containing very less structural defects.