The Synthesis And Optical Properties Of II-VI Semiconductor Nanomaterials

Semiconductor nanomaterials show a potential broad application prospects in nano-optical devices, functional materials and many other fields because of their unique optical, electrical, magnetic and mechanical properties. In recent years, II-VI semiconductor nanomaterials have attracted more and more attentions of researchers for their unique properties in optoelectronics and some other fields.CdS, ZnS and ZnSe, as important II-VI semiconductor nanomaterials, their morphologies are often closely related to their electronic state and properties. Therefore, how to control the reaction conditions to synthesize semiconductor nanomaterials of controlled morphology and size is still a huge challenge. For hydrothermal-solvent method, the factors of affecting the final morphology of product during the experiments have the following points, such as reactant resources, reaction temperature, solvent environment, the surface modification of materials and so on. So in this paper, we have studied some of the factors which impact on the product by XRD, photoluminescence, UV-Visible absorption spectroscopy, Raman spectroscopy, Scanning electron micrographs. All of them were characterized and studied. Further, we also analyse the possible growth mechanism of the nanostructures.The main research work and access to the main content are in the following:1. With cysteine as the sulfur source, we synthesized microspheres of CdS which are self-assembled by CdS nanowires in different ratios of ethylene diamine and water mixtures. We studied the effection of solvent ratio on the morphology, analised the growth mechanism of microspheres, and also studied the effect of different morphologies on their optical properties. Their photovoltaic effect and photocatalytic application are also been studied. In order to improve the crystallinity of nanomaterials, the products are annealed in high temperature so as to enhance the photoluminescence intensity. Different high tempeture and annealed time could lead to different morphologies and photoluminescence.2. We prepared the floc structure of ZnS microspheres in the mixed solvent of ethylenediamine and water. Then we synthesized different morphologies and structures of ZnS products in different solvents and different sulfur sources to comparing the experimental methods. Finally, we systematically analisis the effect of these factors on morphology and structure of products and studied their photoluminescence properties. 3. We prepared Mn-doped ZnSe nanorods. Their morphology and structure were characterized and an appropriate growth mechanism is proposed. We studied the relationship between doped Mn amount and the photoluminescence and make a reasonable theoretical explanation. And we also synthesized Mn-doped ZnS nanomaterials. We studied the morphology, structure and optical properties.