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利用溶胶-凝胶法制备了Mn掺杂和Mn,Li共掺ZnO室温铁磁性半导体,分别采用X射线衍射(XRD),X光电子能谱(XPS),紫外-可见分光光度计(UV-VIS)和振动样品磁强计(VSM)研究了添加Li微量掺杂物对Mn掺杂ZnO的晶体结构、电子价态、能带宽度和铁磁特性的影响。结果表明:添加Li微量掺杂物明显提高了Mn掺杂ZnO的铁磁特性,使Mn掺杂ZnO的饱和磁化强度提高了31.52%;Li+存在于Mn掺杂ZnO晶体结构的间隙位置,晶胞参数a和c略有增加,晶粒尺寸减小;Mn离子均以+2价存在,没有Li和Mn氧化物杂质相的存在;同时,添加Li微量掺杂物使Mn掺杂ZnO的能带宽度减小了0.144 eV,载流子发生变化。铁磁性的提高归因于Li的引入导致ZnO晶格中的间隙电子掺杂和间隙缺陷的产生及载流子的变化,以及Mn2+-Mn2+间接铁磁性交换耦合的增强。
Mn-doped and Mn-Li codoped room-temperature ferromagnetic semiconductors were prepared by sol-gel method and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV- ) And vibrating sample magnetometer (VSM) were used to study the effects of Li addition on the crystal structure, electronic valence, energy bandwidth and ferromagnetic properties of Mn-doped ZnO. The results show that the addition of Li trace dopant significantly improves the ferromagnetic properties of Mn-doped ZnO, and increases the saturation magnetization of Mn-doped ZnO by 31.52%. Li + exists in the interstitial sites of Mn-doped ZnO crystal, The parameters a and c increase slightly, and the grain size decreases. The Mn ions exist at +2 valence without the presence of Li and Mn oxide phases. At the same time, The width is reduced by 0.144 eV and the carrier changes. The improvement of ferromagnetism is attributed to the incorporation of Li into interstitial electron doping and interstitial defects in ZnO lattice and the change of carrier, and the enhancement of indirect ferromagnetic exchange coupling of Mn2 + -Mn2 +.