石英衬底上生长的立方相Zn1-xMnxO薄膜及其光学、磁学特性

Optical and magnetic properties of cubic Zn1-xMnxO thin films grown on quartz substrates

采用电子束反应蒸发法，（MnO）y（ZnO）1-y（y≥0．3）陶瓷靶作为蒸发源，高心含量的Ar/O2混合气为反应气体，在石英玻璃衬底上生长得到Mn含量超过50％（原子分数）的Zn1-xMnxO薄膜。场发射扫描电子显微镜和X射线衍射测量显示x〉O．5的Zn1-xMnxO薄膜呈单一晶相的立方相、岩盐矿结构。这与采用abinifio方法计算得到的结果一致（作为简化，计算时未考虑Mn的自旋的影响），即对于x≥0．5的Zn1-xMnxO材料体系，其取类MnO的立方岩盐矿结构比取类ZnO的六方相纤锌矿结构更稳定。对石英玻璃基Zn1-xMnxO薄膜的紫外．可见透射光谱测量表明，随着Mn含量从0增大到0．68，Zn1-xMnxO薄膜的光学带隙从3．35eV增大到5．02eV．磁性测量结果表明，所制备立方Zn0.32Mn0.68O薄膜在室温下没有表现出宏观磁性．

We report on the reactive electron beam evaporative growth of single-phase cubic Zn1-xMnxO films on quartz substrates using polycrystalline （MnO）y（ZnO）1-y（y≥0.3） ceramic target as source material. The growth was carded out in the environment of Ar/O2 gas mixture with the volume ratio of Ar ： 02 in the range 1：1～3. 1. Field emission scanning electron microscopy （FESEM） revealed unique surface morphology of cubic Zn1-xMnxO film compared with that of hexagonal one. X-ray diffraction （XRD） measurements revealed that Zn1-xMnxO films are of single hexagonal phase, single cubic phase and mixed h＋c phase, corresponding to x=0.25 （as well as that of x=0.12）, x=0.68 and x=0.47, respectively. Such XRD results are consistent with the data obtained from ab initio calculations, i.e., for the Zn1-xMnxO system with x≥0.5, cubic rock salt structure is more stable compared with that of hexagonal wurtzite structure. UV-vis transmission investigations demonstrated that the band gap of Zn1-xMnxO film broadened from 3.35 to 5.02eV along with the increase of Mn content from 0 to 0.68. However, no ferromagnetism is found at room temperature for cubic Zn0.32Mn0.68O film.