Preparation, Doped And Properties Of ZnO Nanorod Arrays

Diluted magnetic semiconductors(DMS)is a kind of material that it can successfully combine the magnetism and electronics in a single substance.DMS is recognized as the base of spin-electron theory,which has some good magnetic performance,magneto-optic and magneto-electric nature,which made its widespreadly applied in such fields as high density nonvolatile memory,magneto-inducer,semiconductor integrated circuit,semi-conductor laser,spin quantum computer,and so on.ZnO,with a wide direct band gap and a large exciton binding energy,have recently attracted much attention due to their novel properties.High density Mn-doped ZnO nanorod arrays with high crystalline quality were vertically grown on ITO substrate via hydrothermal reaction.The microstructure,photoluminescence and magnetism of the arrays had been examined.Some important results are obtained.High density ZnO nanorod arrays with high crystalline quality were vertically grown on ITO substrate via hydrothermal reaction at relatively low temperature of 95℃.The crystallinity, morphology,and structure of ZnO nanorod arrays was examined,effects of the reactant concentration and the reaction time on the size and shapes of the ZnO products were analyzed, and the formation mechanism was also discussed from the angle of nucleation and morphology. A near-band-edge(NBE) emission and weaker deep-level emissions are observed in the ZnO nanorod arrays.ZnO matrix diluted magnetic semiconductor crystals were prepared by hydrothermal method doped with Mn²⁺ and Co²⁺ doped.Morphologies,structures,magnetism and photoluminescence properties characterization are performed by using the transmission electron microscope,X-ray diffractometer,superconducting quantum interference device magnetometer respectively.X-ray photoemission spectroscopy demonstrates that Mn was successfully doped into the nanorods.Meanwhile,all the Mn-doped ZnO nanorod arrays are ferromagnetic at room temperature.The ferromagnetism comes from the ferromagnetic interaction between the Mn ions,but not from Mn oxides impurities.The opticaland magnetic properties were investigated for Co-doped ZnO nanorod arrays. The saturation magnetization decreases with increasing Co concentration because the ferromagnetic interaction,which is as same as Mn deped.PL measurements show that the near-band-edge emission peaks shift to the lower energy side with the increase of Co concentrations.This maybe Co ion decreases the energy gap.