空气退火对ZnS薄膜结构和光学特性的影响

Influence of Annealing in Air on the Structure and Optical Properties of ZnS Films

采用X射线衍射、扫描电子显微镜和光致发光等技术研究了空气退火对ZnS薄膜的结构和光学特性的影响。薄膜在500℃以下退火后结晶质量得到改善,仍呈ZnS立方相结构。退火温度达到550℃时,薄膜中出现ZnO六方相结构。薄膜退火后,大气中的氧掺入薄膜中,出现ZnS-ZnO复合层。随退火温度升高,薄膜晶粒尺寸增大,透过率增加,带隙逐渐接近ZnO带隙。薄膜光致发光结果表明,复合层内ZnS和ZnO绿色发光的叠加替代了来自ZnS缺陷能级间的绿色发光。

The effects of annealing in air on the structure and optical properties of ZnS films were characterized by X-ray diffraction,scanning electron microscopy and photoluminescence,etc.The results indicate that the crystalline quality of the films annealed below 500 ℃ was improved and they still have cubic structure.While the annealing temperature was up to 550 ℃,the hexagonal structure of ZnO appeared in the film.Due to the oxygen in the atmosphere doped into the films,the ZnS-ZnO composite layer appeared.As the annealing temperature increasing,the size of the film grain and the transmittance increased with the energy band gap gradually approaching to that of ZnO.The superposition of the green emissions ascribed to both ZnS and ZnO in composite layer was substituted for the green emission between the energy level of defects of ZnS.