真空蒸发制备CdSe_xTe_(1-x)薄膜及其性能研究

Study of CdSe_x Te_(1-x) thin films prepared by vacuum evaporation and their properties

按不同比例混合CdTe和CdSe两种化合物,利用真空蒸发法在玻璃衬底上制备了CdSex Te1-x三元化合物薄膜,分别利用XRD、SEM、EDX、XPS、紫外-可见分光光度计对薄膜的物相结构、表面形貌、元素组成以及光学性能进行了测试,分析了x值和热处理对薄膜的影响。测试结果表明,薄膜均为立方闪锌矿结构的CdSex Te1-x三元化合物,沿(111)晶面择优生长,晶格常数与x呈线性递减关系;随x值增加薄膜的光学带隙逐渐减小,x=0.57时减小到最小值1.41 eV,然后又增大;升高热处理温度,可以改善薄膜的结晶程度,增加对光的吸收范围,减小光学带隙。

CdSexTel_x films with different chemical composition ratio were prepared on glass substrates by vacuum evaporation. The elemental composition, surface morphology, crystal s：ructure and optical property of the films were examined using EDX, XPS, SEM, XRD and UV-visible spectrophotometer. The effects of composition （x） and annealing on the films were analyzed. The studies reveal that the films exhibit a cubic zinc blende structure with （111） preferred orientation. Linear variation of lattice constant with composition （x） is observed. The ol？tical band gap of the films decreases gradually with the increase of x passing through a minimum （1.41eV） for x=0.57 and then increases. The crystallization, optical transmittance and band gap of the films can be improved by increasing heat treatment temperature.