Synthesize And Characterize Of ZnO Nanostructures

Due to the novel properties of semiconductors depend on their size, shape, and crystalline structure, it is of significant importance to control the shape and size of semiconductors in a controllable way. Among various materials, zinc oxide (ZnO) is an important n-type semiconductor with a wide direct band gap (3.37 eV) and large exciton binding energy of 60 meV. Zinc Oxide (ZnO) is a multi-functional material, which has wide applications in gas sensors, varistors, catalysts and anti-bacterial materials. ZnO nanostructured materials have many novel properties and potential applications in ceramics electronics, optics, chemical technology and biomaterials. ZnO is also bio-safe and biocompatible and hereby can be directly used for biomedical applications without additional coating. To date, many methods including high-temperature vapor deposition and solution-phase method have been developed for preparing ZnO materials of various sizes and morphologies. The vapor deposition route generally used for the preparation of ZnO nanostructures usually need high temperature, expensive equipment and complex procedures which restrict further development in actual applications, while the solution-phase approach allows the growth of these ZnO nanostructures at much lower temperature (less than 200℃) and the preparation techniques are usually economic and can be applied to large-scale production. In the present work, ZnO nano/micro-spheres formed by the aggregation of nano-particles were synthesized by one-step hydrothermal method. The research on ZnO material mainly follows hereinafter aspects:1. ZnO spheres formed by the agglomeration of nano-particles have been synthesized by a hydrothermal method. The as-obtained ZnO spheres are controllable and well reproducible and promising materials for application as photonic crystals and feasible to develop into scale-up production.2. On the basis of the XRD patterns, SEM and TEM images, a possible mechanism to elucidate the formation of ZnO spheres has been proposed. The relative strong and sharp peaks in the XRD pattern confirm that the products are well-crystallized. SEM, FESEM, and TEM images indicate that the products were spheres with smooth surface in the size of about 1μm(±10%).3. During the process of synthesizing nano/micro spheres and the appearance of some interesting experimental phenomena, we summarized that the material rations may impact on the synthesis of ZnO spheres. The size and shape can be effectively tuned by controlling the volume ratio of TEA to H2O in our system under other fixed reaction conditions. In addition, we studied the impact of adding some surface active substance in the reaction system.4. We studied the UV-visible absorption spectra of ZnO spheres produced at different volume ration of TEA to H2O. The spectra show the absorption peak red-shifts as the size increase. The Photoluminescence spectrum reveals that there exist three peaks and the peaks blue-shift as the size decrease.5. The PH values have been investigated when synthesize the ZnO spheres. It should be note that the flower-like spheres composed of interlaced nanosheets were formed.Transition metal chalcogenides including CuS, CdS, ZnS and PbS have attracted considerable attention in recent decades due to their unique physical and chemical properties. They are excellent candidates for scanning microprobe, solid lubricant and energy storage media for lithium and hydrogen. As an important member of copper sulfides, CuS shows p-type semiconductor or metallic conductivity and transforms into a superconductor at 1.6 K, which make it possible to be a promising material for solar cells, optical filters and surperionic materials and so on. To date, CuS nanocrystals with special morphologies have been synthesized such as nanodisks, urchin-like, hollow spheres, shrub-like, microrods and chrysanthemum-like architectures. Many methods have been developed for preparing CuS, including microwave, electrosynthesis, thermolysis and so on. However, most of these synthetic methods involve template or complex equipment. Aqueous (including hydrothermal) route and nonaqueous (including solvothermal) route have been widely used to prepare inorganic materials. This paper presents a facile method to fabricate CuS porous microspheres, which was formed by the intergrowth of CuS polycrystalline nanoslices. The research on CuS material mainly follows hereinafter aspects:1. CuS microspheres of high quality consisted of nanoslices was prepared by single-step solvothermal route at low temperature. The as-obtained CuS spheres are controllable and well reproducible and feasible to develop into scale-up production.2. On the basis of the XRD patterns, SEM and TEM images, a possible mechanism to elucidate the formation of CuS spheres has been proposed.3. During the process of synthesizing CuS spheres and the appearance of some interesting experimental phenomena, we summarized that the material rations, reaction time and temperature may impact on the synthesis of CuS spheres. In addition, we studied the impact of adding some surface active substance in the reaction system.4. We studied the optics character of the as-obtained CuS sphere, including UV–vis diffusion reflection and laser Raman.5. The ammonia gas detection at room temperature on CuS has been studied.