Influence of lead concentration on morphology and optical properties of Pb-doped ZnO nanowires

Undoped and Pb-doped ZnO nanowires with different lead concentrations were grown on Si(111) substrates using a thermal evaporation method. Scanning electron microscopy (SEM) results showed that, the undoped ZnO nanowires were well aligned with uniform diameters and lengths. On the other hand, the Pb-doped ZnO nanowires were tapered and not aligned in a unique direction. X-ray diffraction patterns and Raman measurements clearly indicated hexagonal structures for all of the products. In addition, the Raman results demonstrated that the Pb-doped ZnO nanowires had a lower crystalline quality than the undoped ZnO nanowires. Photoluminescence (PL) studies also confirmed the Raman results and showed a lower optical property for the Pb-doped ZnO nanowires compared to the undoped ZnO nanowires. Moreover, the PL results showed a smaller band-gap for the Pb-doped ZnO nanowires compared to the undoped ZnO.