Preparation By Using Template And Characterization Of CdS Semiconductor Nano-material And Its Growth Mechanism

The purposes of this dissertation are to study template preparation, characterization and the growth mechanism of CdS nanomaterials, such as nanowires, nanoparticles and nanotubes. These templates include aluminum anodic oxide (AAO) membrane, monolayer and surfacetant. By utilizing templates, electrochemical techniques and chemical methods, CdS nanomaterials were assembled and scanned with the help of modern physical methods. CdS nanowires were assembled in the nanoporous of AAO template by alternating current (A.C.) and direct current (D.C.) electrodeposition. TEM and XRD investigations demonstrate that these nanowires have the crystalline structure of hexagonal CdS crystal and the epitaxial growth in some direction. Meanwhile, a mechanism for the CdS nanocrystallites growth was put forward.Besides, CdS semiconductor particle films were obtained under arachidic acid monolayer, floating on cadmium nitrate solution, by injection of S2－ aqueous beneath the monolayer. Different shapes of the CdS semiconductor nanocrystallites were formed under different surface pressure of monolayer. The influence of surface pressure of monolayer preparation of arachidic acid on the structure of CdS nanocrystallites was studied by TEM images and electron diffraction patterns. A mechanism for the CdS nanocrystallites growth was discussed in terms of divalent metal ion binding to the carboxylate head group of arachidic acid monolayer at air/water interface.At last, an ultraviolet irradiation has been the synthesis of CdS nanocrystallites with different morphologies using polyvinyl alcohol (PVA) as a protecting agent, which self-assembles into the desirable shapes. This method may extend to synthesis other metal sulfide nanocrystallites, nanowires, nanodisks, and even nanotubes.