Low-Temperature Growth of Flower-Shaped UV-Emitting ZnO Nanostructures on Steel Alloy by Thermal Evaporation

Flower-shaped ZnO nanostructures, containing the triangular-shaped petals (sharpened tips and wider bases) have been achieved by simple thermal evaporation of high purity metallic zinc powder in the presence of oxygen at 440 °C on steel alloy substrate without the use of metal catalyst or additives. Detailed structural studies confirm that the obtained flower-shaped nanostructures are single crystalline and possesses a wurtzite hexagonal structure, grown along the c-axis in the [0001] direction. Raman and room temperature photoluminescence analysis substantiate a wurtzite hexagonal phase with a good crystal quality and a strong UV emission at 378 nm, respectively, indicating few or no structural defects. Additionally, a detailed possible growth mechanism has also been discussed.