| Diluted magnetic semiconductor (DMS) material is one of important parts of spintronics. It has attracted widely attention for its novel properties, such as giant magnetoresistance and huge magneto-optical effect, etc. To obtain room-temperure ferromagnetism is a problem in DMS study. ZnO is a wide band-gap semiconductor with the high exciton binding energy of 60 meV. Room-temperature ferromagnetism has been predicted in Mn-doped ZnO. The ZnO-based DMS therefore attracts extensive interesting.This thesis was focused on the preparation of Mn-doped ZnO, studying their physical properties, such as the structural, optical and magnetic properties. There are three main parts of this paper, which can be summarized as follows:1. Mn-doped ZnO nanofilms were fabricated using absolute ethanol. The effects of dopant concentration and annealing temperature on structural, optical and magnetic properties were investigated. The lattice constants increase with increasing Mn content, indicating Mn entering in the ZnO lattice. Mn passivates the visible emission, improving the optical quality. The sample annealed at lower temperature show paramagnetism in the range of 4K-300K. The magnetism origin of the sample annealed at higher temperature is attributed to ZnMn2O4.2. The nanoparticles with 2.2-2.8nm diameters were synthesized using diethylene glycol. The optical and magnetic properties were investigated. Compared to pure ZnO, the doping samples exhibit increasing optical quality. The samples show the ferromagnetism with high Tc above room temperature, which origins from Mn doped ZnO rather than impurities.3. The high quality Zn1-xMgxO nanofilms were fabricated. The band gap increases... |
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