Ni-doped vertically aligned zinc oxide nanorods prepared by hybrid wet chemical route

Ni-doped zinc oxide (Ni:ZnO) nanorods were synthesized by incorporating nickel in vertically aligned ZnO nanorods. Ni was evaporated onto ZnO nanorods and the composite structure was subjected to rapid thermal annealing for dispersing Ni in ZnO nanorods. The optical band gap decreased with increasing amount of Ni incorporation. The origin of the photoluminescence peak at ∼ 400 nm was related to the defect levels introduced due to substitution of Ni2+ in the Zn2+ site with annealing. The Raman spectra indicated the presence of the characteristic peak at ∼ 436 cm− 1 which was identified as high frequency branch of E2 mode of ZnO. The Fourier Transformed Infrared spectra indicated the existence of the distinct characteristic absorption peak at 481 cm− 1 for ZnO stretching modes. Current–voltage characteristics indicated that the current changed linearly with voltage for both the doped and undoped samples.