带隙可调的CdS纳米晶薄膜的化学浴制备和光学性质

Chemical Bath Deposition and Optical Properties of CdS Nanocrystalline Films with Tunable Electronic Band Gap

CdS是一种直接带隙半导体,室温下其禁带宽度约为2.4eV,是一种良好的太阳能电池窗口层材料和过渡层材料。分别以CdCl2和(NH2)2CS作为镉源和硫源,用化学淀积法在玻璃上生长CdS纳米薄膜,考察了Cd2+浓度、淀积温度、淀积时间以及溶液pH值对CdS成膜的影响。紫外可见光吸收谱和荧光光谱的结果表明,在样品的制备过程中,通过改变反应条件如化学试剂的浓度、加热温度、加热时间等来控制薄膜中颗粒的尺寸大小,随着反应温度的逐渐降低或反应时间的减少等可以使得到的CdS纳米晶薄膜中晶粒尺寸逐渐减小,带隙增加;镉离子浓度越小或氨水浓度越大,所得CdS纳米晶薄膜带隙越大。

Group Ⅱ-Ⅵ semiconductor CdS with a direct band gap of 2.4 eV at room temperature has attractive photonic properties, which is suitable for window layer and buffer layer material of solar cells. CdS nanocrystalline films were grown on glass substrates by means of chemical bath deposition technique with CdCl2 as the Cd ions and （NH2） 2CS as the S ions source. The concentration of Cd ions, deposition temperature, deposition time and pH value have effects on quality of CdS nanocrystalline films. UV-Vis absorption spectra and PL spectra indicate that the change of concentration of Cd ions, deposition temperature, deposition time and pH may adjust the band-gap of CdS nanocrystalline films.