Studies On The Crystal Structure, Magnetical And Optical Properties Of ZnO Doped With Transition-metal

We have fabricated ZnO films doped with transition-metal as Fe,Co,Cu in different conditions by using electron beam transpiration method.By analyzing their XRD spectra,we have systemly discussed the crystal structures in different conditions ,such as substrate types, substrate temperature, different O2/Ar ratio K , annealing temperature and Cu contents. We have found the best ways to optimize the growth of quality ZnO films and got highly c-axis oriented ZnO films.The microstructures of the films were observed by AFM.After analyzing the crystal structures, the crystal tropism and the surface conformation flatness,we found the result that the substrate temperature of 400癈 is ideal for silicon substrates,which conforms to the result of the structure analyse.By analyzing the magnetism of ZnO films,we found that the films appropriately doped with Fe,Co ions have magnetism at room temperature and their magnetism can be improved by doping other little Cu ion,but it is not certain that the content of Cu is higher,the film has more magnetism,so it has the best content of Cu.Moreover, the films which have best crystal structures may not have the best magnetism. We also have analyzed the photoluminescence (PL) spectra of some ZnO films,it turns out that the emission of ultraviolet light comes from the radiative recombination of excitons within nano-crystal energy band-gap, and the PL peaks move to smaller wavelength because Zn are substituted by Fe,Co,and Cu,which cause the size of the film grains smaller and the effective band-gap bigger.The red emission of ZnO films is due to,on the one hand, decrease of the film grains size which causes the emission intensity smaller and smaller until it disappears abruptly,on the other hand, the transition of electrons from deep donor level of the oxygen vacancies to the valence band.