Study On Electronic And Magnetic Properties Of ZnO-based Dilute Magnetic Semiconductor

In this paper,ZnO nano-crystalline doped with Co and Mn were synthesized by hydrothermal method,respectively.The electrical and magnetic properties of as-prepared and annealed samples were investigated in detail.The structure and morphology of the products were characterized by XRD and SEM.The electrical transport properties and magnetoresistance effects of the samples were analyzed by the Hall Effect test system.The results are as follows:The XRD results of Zn_1-xCo_xO showed that Co ions incorporates into the Zn O lattice successfully with 2+ valence state,the substitution of Co2+ for Zn2+ does not change the original wurtzite structure of zinc oxide,but the position of peak has shift with the change of doping concentration.The SEM shows that all samples have different morphology.And the result of XPS,Raman and FTIR showed that Zn0.9Co0.1O were relatively pure.All sample showed positive MR effect.The sample of Zn_1-xMn_xO also showed hexagonal wurtzite structure.The XRD shows that peak position has a shift to the left and the lattice constant becomes larger.After annealing,the size of sample was increased.The crystal quality was increased with the increase of doped Mn concentration.And the result of XPS,Raman and FTIR showed that Zn0.85Mn0.15 O were pure relatively.The samples without annealing showed negative magnetoresistance effect,which was mainly due to the combination of electron localization and band splitting,After annealing,samples shows positive magnetoresistance,the reason was the enhancement of the electron locality.The result of Hall Effect and the magnetoresistance effect were consistent.