Highly conductive Al-doped tetra-needle-like ZnO whiskers prepared by a solid state method

Tetra-needle-like zinc oxide whiskers (T-ZnOW) were doped with Al3+ by a solid state method. In this study, modification conditions were thoroughly investigated to obtain low resistivity T-ZnOW, without destroying the tetra-needle-like structure. The Al-doped T-ZnOW was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transition infrared (FT-IR) spectra and electrical resistance measurement. The SEM and XRD results indicated that the tetra-needle-like structure of ZnO whiskers could be well maintained after modification and the doped (0 0 2) face was preferred. FT-IR results showed that the decrease of resistivity of Al-doped T-ZnOW resulted from formation of [AlO4] configuration in T-ZnOW bulk. Experiment results showed that the annealing temperature, doping concentration and type of Al sources affected the resistivity of T-ZnOW considerably. The optimum Al-doped concentration was 7.0 at.% and the resistivity of T-ZnOW could be considerably decreased from 108 to 102 Ω cm.