Preparation And Photocatalytic Properties Of Semiconductor Micro - Nanostructured Materials

Semiconductor materials in micro-nano scale structure show more excellent physical and chemical properties than traditional materials due to their unique structures, so they have a lot of potential application in many fields, such as defense、 electronic、 aerospace、 chemical and so on. The research of the preparation and properties of micro-nano semiconductor materials has been a hot topic in the industry and arouse much interest of scientists all over the world.In this paper, we successfully prepared micro-nano semiconductor materials with different structure and morphology and the performance of the various aspects of the above-mentioned material samples were tested and analyzed. The specific content is as follows.Firstly, hollow flowerlike nanostructure ZnS were synthesized through hydrothermal method by changing the solvent and PH Value, and then annealed at550 ℃,600 ℃,650 ℃respectively to achieve ZnO and ZnS II hetero-junctions. The results indicated that oxygen atoms acquired enough thermal energy during annealing which replaced the sulfur atoms in the lattice and sulfur atoms diffused out of the sample, the ZnS gradually transformed into ZnO with the increase of annealing temperature. When the annealing temperature was elevated to 600 ℃, ZnO/ZnS type-II hetero-junction was formed, when the annealing temperature went up to 650 ℃, the product was almost composed of ZnO. The Roman results further indicated the transformation. UV-Vis results suggested that the band gaps of the samples decreased as a whole during annealing. Among those samples, ZnO/ZnS type-II hetero-junction had the best catalystic behavior, this may be due to its strong separation of electrons and holes via the interface between ZnO and ZnS type-II hetero-junction.Secondly, through hydrothermal method, we prepared the samples of Mn-doped CdS nanoparticles, different samples were formed by controlling the reaction conditions. XRD analysis showed that all of the samples have hexagonal wurtzite phase structure, and crystallinity of the sample decreased with the increase of the concentration of the doping. EDS results suggested that Mn element content in the sample gradually rised with the improvement of the doping concentration of Mn2+. The Roman results further confirmed the Mn2+ions doped to CdS, hyperfine coupling constant indicates that Mn2+ ions are in a slightly distorted tetrahedral crystal field. Based on the research of the Raman spectrum analysis, we obtained some phenomenon. We observed 1LO,2LO of CdS, also found that as the sample size is increased, exciton phonon coupling strength enhanced, while with the improvement of the doping concentration of Mn2+, exciton phonon coupling strength reduced.Thirdly, a simple and green strategy is presented to fabricate CuO quantum dot-assembled nanospheres based on laser ablation in water. SEM, TEM, HRTEM and XRD results showed that the colloidal nanospheres are mesoporous, with an average size of approximately 200 nm. Furthermore, the quantum dots, as a building block, can be easily tuned in size by changing the laser power, and tuned in shape by additional electro-field. Importantly, such mesoporous nanospheres exhibit good photocatalytic activity due to their unique structure.