化学浴沉积ZnSe薄膜材料的结构和光学特性

STRUCTURAL AND OPTICAL PROPERTIES OF ZnSe THIN FILMS FABRICATED BY CHEMICAL BATH DEPOSITION

采用化学浴沉积(CBD)制备不同膜厚的Zn Se薄膜,用扫描电子显微镜(SEM)和X射线衍射(XRD)分析薄膜结构,结果显示薄膜为纳米晶立方相闪锌矿结构,平均晶粒尺寸约为200 nm,结构致密,(111)晶面择优取向。使用分光光度计测得薄膜透射谱与反射谱,计算和分析材料在可见光区域的吸收系数、消光系数、折射率、光学能隙。结果表明,薄膜透过率、反射率均随膜厚的增加而降低,薄膜在本征吸收区域吸收系数很大,且随波长的减小而增大。膜厚为150、400、630 nm材料对应的光学能隙值分别为3.16、3.14、3.07 e V。

Zn Se nano-crystalline thin films with different thicknesses are grown by chemical bath deposition. SEM andXRD are used to investigate the structure properties. Results showed that thin films have zinc-blende structure with（111）preferred orientation and compact structure,mean grain size is around 200 nm. Transmission and reflectionspectrum of the films are also measured by spectrophotometer,optical properties like absorption coefficient,extinctioncoefficient,refraction index and the energy gaps are calculated and analyzed in visible wavelength region. It is found thattransmittance and reflectance decrease with the increase of film thickness,absorption coefficient in intrinsic absorptionregion is very high and increases with the decrease of wavelength. Energy band gap values of 3.16,3.14,3.07 e V areobtained when film thickness are 150,400,630 nm,respectively.