Of Znse Semiconductor Nanomaterials Liquid Phase Synthesis And Characterization

ZnSe, as an important wide bang-gap (2.68 eV)â…¡-â…¥semiconductor, has attracted much attention for their applications in photoelectronic devices, such as blue light-emitting diodes and blue-green diode lasers. So, it is significant for developing strategies to fabricate ZnSe nanomaterials.In recent years, many research groups have developed various strategies to fabricate ZnSe nanosturctures, such as hot-injection methods, reverse micelles methods, spray pyrolysis and so on. Nevertheless, most of these synthetic routes involved expensive devices, complicated technics, and difficulty to achieve industrialization. Seeking reasonable synthetic methods and making the shape control of the nanoparticles have become one of the key technologies for fabricating ZnSe nanocrystals. Hydrothermal/solvent thermal technique has become a commonly used method for synthesis of nanostructures because of its simple process, low investment and low pollution. In this thesis, ZnSe colloidal microspheres have been synthesized via hydrothermal/solvent thermal routes. The main contents are follows:1. Hydrothermal Sythesis of Monodisperse Nanostructured ZnSe Spheres at Low Temperature.Submicronspheres of Zinc Selenide(ZnSe) have been synthesized by hydrothermal route using Na₂SeSO₃ and ZnSO₄-7H₂O as Se and Zn sources. In this system, NaOH aqueous solution was used as the reaction medium and PEG 2000 as surfactant. XRD, TEM, XPS, PL were used to characterize the phase structure and properties. The results show that the average diameter of submicronspheres is about 210nm, and the absorption peaks have obviously blue shift compared with the conventional bulk material zinc selenium. The influence of surfactant on the as-prepared ZnSe nanomaterials' morphology, size is also been studied.2. Alcohoothermal Sythesis and Characterization of ZnSe Hollow Microspheres.ZnSe microspheres were prepared at 140～200℃for 6-18h by alcohothermal route using Zn(CH₃COO)₂-2H₂O and Na₂SeO₃ as source materials and ethylene glycol(EG) as reducing agent, dissolved in NaOH aqueous solution. The influences of processing parameters on the grain size, morphology and optical properties of ZnSe powders were inversigated, such as volume ratio of H₂O:EG, the molar ratio of Zn:Se, concentration of NaOH, alcohoothermal temperature, soaking time and so on. XRD, SEM, HRTEM were used to characterize the phase structure and morphology. XPS was used to analysis the combination of elements in the compound state. Optical spectrum spectra of the ZnSe hollow microspheres were measured by US-VIS spectrometer. The research results show that the powders were cubic blende ZnSe and reducing agent ethylene glycol was necessary to prepare pure ZnSe.