Solvothermal Synthesis Of Ⅱ-Ⅵ Semiconductor Nanocrystals

The present thesis is focused on the shape-controlled syntheses of CdTe, ZnTe, ZnO, CdO nanocrystallites by the adoption of new reaction system and varying the experimental parameters via solvothermal method. The crystal structure, morphology and optical properties of the products were investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM) and ultraviolet-visible spectrophotometer (UV-vis spectra), respectively. The main work completed in this thesis can be summarized as following:1. CdTe nanobelts with thickness of 100nm, width of 200nm-400nm and length of 2-3μm were synthesized under a hydrothermal condition by adopting cadmium chloride hemidihydrate (CdCl₂·2.5H₂O) and tellurium (Te) as sources, potassium borohydride (KBH₄) as reducing agent. The effects of reaction temperature, sources of cadmium and reaction time on the morphology and structure of the products were studied, and the formation mechanism of the nanobelts was discussed.2. ZnTe microflakes with blende structure were synthesized under a hydrothermal condition by zinc (Zn) foil and tellurium (Te) powder as sources in ethylenediamine. Microflakes are about 2μm in length and about 300nm in width. The surface of the flakes is rough and includes large number of nanorods and nanoparticles.3. ZnO nanoflowers with wurtzite structure were synthesized under a hydrothermal condition by choosing Zn(CH₃COO)₂·2H₂O and NaOH as sources in mixed solution of ethylene glycol and water. The overall size of ZnO nanoflowers are about 600nm. The petals are about 300nm in length and 100nm in width.4. CdO nanoflakes were synthesized under a hydrothermal condition by adopting CdCl₂·2.5H₂O and NaOH as sources in mixed solution of ethylene glycol and water. The nanoflakes are about 80-100nm in thickness and about 0.3-1.5μm in diagonal.