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In this work where obtained bismuth sulfide thin films, by a simplified formulation, the method used for the synthesis of bismuth sulfide thin films, is denominated chemical bath deposition. It was determined the optical absorption characterization showed a direct bandgap between 1.3eV and 1.6eV. Scanning electron microscopy images are also reported, which shows homogeneity in the morphology of the obtained films, as function of the deposition time. When analyzing the material by transmission electron microscopy technique, it was obtained an interplanar distance of 3.11Å, also characterized by X-ray diffraction obtaining a main signal in 2Î, = 27.3°. [ABSTRACT FROM AUTHOR]

We present the annealing effects on ammonia-free CuxS thin films using Triethanolamine and barium hydroxide as ligand agents by chemical bath deposition method. We synthesize two different samples: one as ground and the other with thermal treatment at 180°C. The X-ray diffraction showed an amorphous nature for both samples. It was established from reflection and transmission measurements that the direct energy band gap obtained was 2.57 eV as ground and 2.52 eV for annealing samples and the indirect energy band gap obtained was 1.365 eV as ground and 0.98 eV for annealing. The morphology was studied by Atomic Force Microscopy, where we obtained roughnesses of 19.128 nm and 23.506 nm for the thin films without and with thermal treatment, respectively; and the cluster sizes, which were between 87 - 200 nm ranges as ground sample and 136 - 247 nm range for annealed sample. The CuS (covellite) with amorphous structure was obtained. The resistivity of ? ≅ 10 - 3 Ω cm was measured using Four Point Method. The chemical element composition was obtained by using XRay Photoelectron Spectroscopy. Complementary characterization of Raman Spectroscopy and Transmission Electron Microscopy were carried out. [ABSTRACT FROM AUTHOR]

The CdS thin films using Acetylacetone as complexing agent were prepared using the chemical bath deposition method, with bath temperature of 70°C with differences times of reaction. The thin films were characterized by X-Ray diffraction (XRD), Scanning Electron Microscopy (SEM), optical absorption spectroscopy and Atomic Force Microscopy (AFM). The XRD measurements showed that the films have hexagonal polycrystalline structure and the crystallites are oriented preferentially with the (002) and (110) planes. The optical absorption measurements shows the presence of direct transition with energy band gap of 2.37 eV and after increased to 2.40 eV. [ABSTRACT FROM AUTHOR]

The interesting applications of ultrathin silica films on transition metals drove us to analyze the interactions between them. We selected only sixteen transition metals to observe a pattern and started at a molecular level to understand the principal interactions involved between them. A conformational search and a subsequent optimization of the structures, together with frequency calculations at the MP2/LANL2DZ level of theory for the metals and MP2/6-31G* for the rest of the atoms. The results show that the interactions are favorable with the transition metals we selected. [ABSTRACT FROM AUTHOR]

In this work resistance and resistivities of PbS thin films by chemical bath deposition using Polyethylenimine as complexing agent are presented. A series of resistance and resistivity values of thin films obtained at different deposition times of 7, 10 and 13 minutes were evaluated and compared. The obtained films were chemically characterized by X-Ray Photoelectron and Raman spectroscopy confirming the presence of lead and sulfur as PbS. Thickness of the films was measured by ellipsometric spectroscopy; the values were in the range of 80 to 100 nm. Resistivity of the films was measured indirectly using an integrator circuit, the results show that resistivity values vary as a function of the deposition time. PEI films showed a low transmission in the visible range about 2 to 5% and an irregular absorption in the range of 300 to 1050 nm. Roughness of the films was characterized by atomic force microscopy showing values of mean square roughness of 16 nm, presenting different orientation of the clusters and pyramidal shapes. [ABSTRACT FROM AUTHOR]