Intrinsic defects, impurities and doping in ZnO nanorods grown at low temperature

We report on the defect properties of single-crystalline ZnO nanorods grown from solutions at temperatures below 90 A degrees C. The nanorods can easily be doped by providing impurity precursors during growth. In the as-grown state the nanorods exhibit considerable lattice strain and distortions which compromise their electrical and optical properties. Upon annealing at moderate temperatures of < 400 A degrees C the lattice strain is converted into dislocation-type defects, and the dopant impurities become optically active. In the annealed state the near-bandgap photoluminescence quantum efficiency is improved more than 5 times and reaches similar to 16 % at room temperature. Thus with moderate annealing, interesting device applications become feasible for nanorods grown at T < 90 C-a similar to.