Synthesis and optical properties of PbS/ZnO composite films

Pure ZnO films and PbS/ZnO nanocomposite films of optical quality were prepared with a sol–gel method. The particle size, optical absorption, and linear refractive index of the PbS/ZnO films were measured by TEM (transmission electron microscopy), UV-Vis absorption, and ellipsometry techniques, respectively. For high Pb/Zn ratios, PbS particles of size 5–8 nm are observed in TEM, and a large refractive nonlinearity of 10−7 esu with a saturable absorption was measured in picosecond Z-scan experiments.