化学水浴沉积法制备硫化镉薄膜的微结构和性能

Microstructure and Properties of Cadmium Sulfide Thin Films Prepared by Chemical Bath Deposition

采用化学水浴沉积法在不同氨水用量下制备了Cu(In,Ga)Se_(2)太阳能电池的缓冲层CdS薄膜,根据化学平衡动力学计算出混合溶液中反应粒子的初始浓度、pH值和离子积,利用台阶仪、扫描电子显微镜(SEM)、X射线衍射仪(XRD)、量子效率测试仪(EQE)和IV测试仪对制备样品的薄膜厚度、表面形貌、晶体结构、量子效率和光电转换效率进行了表征和分析。结果表明:提高氨水用量可以抑制同质反应,促进异质反应,使CdS薄膜晶体结构从立方相向六方相转变,晶粒形状从柳絮状向颗粒状转变,晶粒尺寸逐渐增大,粒径分布更加均匀,薄膜表面更加平整,制备电池的EQE、V_(oc)、J_(sc)、FF、R_(s)等电学参数得到优化,光电转换效率从7.64%提高到13.60%。

CdS thin films for the buffer layer of Cu(In,Ga)Se_(2) solar cells were prepared by chemical bath deposition at different ammonia dosages.The initial concentration,pH value and ion product of the reaction particles in the mixed solution were calculated according to the chemical equilibrium kinetics.The film thickness,surface morphology,crystal structure,external quantum efficiency and photoelectric conversion efficiency of the samples were analyzed by step tester,SEM,XRD,EQE and IV tester.The results show that with the increase of ammonia amount,the homogeneous reaction rate reduces because the free Cd2+concentration decreases,and the heterogeneous reaction rate increases because the Cd(OH)2(NH3)n density adsorbed on the substrate surface increases;the crystal structure of CdS thin films changes from cubic phase to hexagonal phase because the cubic phase is formed by the homogeneous reaction,and the hexagonal CdS thin film is formed by the heterogeneous reaction;the surface morphology changes from loose porous structure formed by physical adsorption of large round particles to uniform and dense thin film grown by liquid phase epitaxy,the grain shape changes from willow catkins to granular,the grain size gradually increases,the particle size distribution is more uniform,and the film surface is smoother;the electrical parameters such as EQE,V_(oc),J_(sc),FF and R_(s) are optimized,and the photoelectric conversion efficiency increases from 7.64%to 13.60%.