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Controlled Synthesis, Property Modulation of Zinc-based Semiconductor Nanomaterials

Author: YuXiaoMing
Tutor: ChengBaoChang
School: Nanchang University
Course: Materials Physics and Chemistry
Keywords: Semiconductor Doping Controlled growth Bandgap engineering
CLC: TB383.1
Type: Master's thesis
Year: 2008
Downloads: 55
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Abstract


Controllable morphology and properties of nanomaterials become the main theme of the new stage of the study. ZnO and ZnS nanomaterials object of study, the development of a simple, energy saving, fast and easy large-scale production of the combustion method to prepare the magnesium or cadmium-doped zinc oxide nano-materials, and is controlled by the introduction of the dopant ions to the ZnO the growth of the material and to adjust its optical properties. Main results are as follows: 1, prepared by the method of low temperature combustion (ZnCd) O, Cd added in the raw material can influence the morphology of the product, mainly to generate half curled ribbon product. Cd is dissolved in the lattice to the occurrence of a certain degree of distortion makes E the high non-polar Raman modes blue shift. 5% of Cd-doped sample annealed at 600 ℃ solution Cd concentration is higher, thereby forming a deeper LEVEL issued about 600nm red-orange emission. Annealed at 1000 ℃, Cd desolventizing precipitation generated cubic CdO phase makes the band-edge emission becomes bimodal emission in the visible region becomes the dominant CdO about 525nm emission. Cd content and annealing temperature changes, the band-edge emission peak does not appear particularly obvious red shift, after its further studies lay the foundation for the application of ultraviolet light-emitting diodes, UV laser. 2, prepared by the method of low temperature combustion (ZnMg) O, with Mg added in the raw material capable of forming a curled flake product. Mg content is high, will generate a wide band gap of Zn-doped MgO inclusions in Mg-doped ZnO outside, such that the emission is greatly enhanced. Since bandgap UV emission and green emission ratio increases with the increase of the excitation intensity, and green emission means defects may come from a shallow donor level in the near band edge to the doubly charged oxygen vacancies transition. Mg-doped ZnO bandgap emission peak blue shift high Mg content, not only to adjust the band gap, and better able to form the quantum confinement effect and makes the band-edge emission enhanced. 3, using the of simple catalyst thermal evaporation method successfully synthesized silica uniformly wrapped the ZnS ball structure, in a horizontal tube furnace. Was found by TEM, the main core portion is a hollow structure, and the core portion there not be fully restored decomposed ZnS nanoparticles or nanorods, resulting sample light emitting 460nm of ZnS defect exists. This amorphous structure containing a large number of single-quality microcrystalline silicon, which leads to a strong red-orange emission.

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