Mg掺杂ZnO薄膜的结构和光学性质

Microstructure,optical properties of Mg-doped ZnO thin films

采用磁控溅射方法在硅和石英衬底上制备了纯ZnO和Mg0.04Zn0.96O薄膜.用XRD和AFM表征薄膜的晶化行为和显微结构,用透射谱和光致发光谱分析薄膜的光学性质.分析结果显示:两种薄膜均为六角纤锌矿结构,且沿c轴取向,薄膜表面光滑致密,晶粒分布均匀;薄膜在可见光范围内具有较高的透过率,Mg掺杂后透射谱吸收边向高能侧移动,相应的薄膜的带隙宽度从3.28 eV升至3.36 eV;用包络法计算出薄膜的光学常数表明,Mg掺杂没有明显改变薄膜的折射率,但使消光系数明显增大;薄膜的光致发光谱分析也发现,掺入Mg使带边发射峰蓝移.

The pure and 4 mol% Mg- doped ZnO thin films were prepared on p- Si（100） and fused quartz substrates by r. f. magnetron sputtering at room temperature. Both the doped and undoped films exhibited hexagonal structure and showed a strong （002） orientation.The optical constants, such as refractive index （n） and extinction coeffcient （k）, were obtained from the transmittance spectra using envelope method. The results revealed that the refractive index（n） had no obvious defference as Mg doping, however the extinction coefficient （k） increased. The band gap Eg was also obtained from the transmittance spectra. It can be observed that the Eg incresed as Mg doping. The photoluminescence （PL） studies showed that the peak related to the near band emission shifted to the high energy, which agreed with the result of the transmittance spectra.