Structural and optical properties of Cu-, Ag, and Al-doped zinc oxide nanorods

• Properties of Cu, Ag, and Al-doped ZnO nanorods were investigated.
• Undoped, Cu, and Ag-doped ZnO nanorods showed a preferential orientation along c-axis.
• Alignment and length of nanorods were improved with incorporation of Cu dopant.
• Randomly-oriented ZnO:Al microrods were grown on the ZnO seed layer.
• All nanorods exhibited good transparencies in the visible region.

We investigated structural and optical properties of Cu-, Ag-, and Al-doped zinc oxide (ZnO) nanorods grown on ZnO seed layers. Cu-doped ZnO (ZnO:Cu) nanorods showed increased length and improved crystallinity, compared to undoped ZnO nanorods, where the average transmittance in the visible region is lower than that of ZnO nanorods. Meanwhile, the Ag incorporation led to quite opposite behaviors: decreased length and crystallinity of nanorods. It was also found that Ag-doped ZnO (ZnO:Ag) nanorods exhibited high transparency. The incorporation of Al dopant led to a marked morphological variation, with randomly oriented microrods grown on the surface of the ZnO seed layer, instead of nanorods. Al-doped ZnO (ZnO:Al) microrods exhibited excellent transparency over the visible region. The present results thus show that incorporation of Cu, Ag, and Al dopants has a critical effect on structural and optical properties of ZnO nanorods.