采用溶胶-凝胶技术和旋涂的方法,在Si(100)衬底上制备了Ni掺杂和(Ni、Li)共掺的3种ZnO薄膜(Ni0.10Zn0.90O、Ni0.10Li0.05Zn0.85O和Ni0.10Li0.10Zn0.80O)。X射线衍射分析表明,所有薄膜样品均为纤锌矿结构,未发现其他杂相。光致发光研究表明,(Ni、Li)共掺后出现了410nm左右的紫外发光峰,并随Li浓度的增加发光峰变强,该峰与Li杂质能级有关,同时观察到O2-空位引起的610nm和740nm的两个红色发光峰。薄膜中Ni离子为+2价,取代Zn离子的位置。掺杂的ZnO薄膜呈现室温铁磁性,单个Ni原子的饱和磁矩可达到0.210μB,掺入Li或在N2气氛中退火后,都导致单个Ni原子的饱和磁矩降低。铁磁性来源于电子调制的机制。
Ni-doped and (Ni, Li) -co-doped ZnO thin films (Ni0.10 Zn0.90O, Ni0.10Li0.05Zn0.85O and Ni0.10Li0.10Zn0.80O) were generated on Si (100) substrates'by sol-gel and spin-coating technique. The films were wurtzite in structure and no other phase was found by X-ray diffraction. In (Ni, Li) -co-doped ZnO thin films, the photoluminescence spectrum recorded at room temperature displayed Li-related ultraviolet band at about 410 nm, which increases with rise in Li concentration. Furthermore, O2- defect-related red luminescence at about 610 nm and 740 nm were observed. The chemical state of Ni was found to be bivalent by X-ray photoelectron spectroscopy, it is replacement of Zn2+ by Ni2+ in the ZnO lattice. All the films were ferromag- netic at room temperature, and saturated magnetic moment for each Ni can reach to 0. 210 μB. Moreover, saturated magnetic moment for each Ni declined when Li was infilled or films were annealed in nitrogen. The electrons-mediated mechanism is suitable for the explanation of ferromagnetism of doped ZnO films.