| Semiconductor quantum dots are receiving increasing attention and widely used in many industries because of their unique properties.In recent years,the research of semiconductor quantum dots which involved by chemical synthesis,material science,biological analysis etc,has very extensive application value and great exploitation foreground.As a new biological probe,fluorescent semiconductor quantum dots have lasing safety brought profound changes of research methods and means in the field of bio-medicine.The study of CdTe quantum dot because of its quantum confinement effect has become the hot spot in materials physical researches,and the discussion of its application in solar battery,sensor device just starts now.Therefore,it is very important to clarify the absorption mechanism of the quantum dots.In this paper,the fabrication and characterization of CdTe quantum dot is the first work.In the preparation of quantum dots,we improve the preparation method of sodium borohydride to save a lot of time to improve its quality.Five different sizes of CdTe quantum dot are made successfully,and Visible spectra and spectroscopy of samples are researched to find the influence of the different quantum dot size on Visible spectra and spectroscopy.Nonlinear optics and ultrafast dynamics are the paper mainly studies,the nonlinear absorption,nonlinear refractive index and third-order nonlinear optical coefficient are measured by femtosecond Z-scan to compare the influence of quantum dot sizes.Experimental results show that the nonlinear absorption increases accordingly with the decreasing of quantum dots size.The ultrafast optical physical properties of the sample is researched and the exciton dynamics life is fitted by the technology of pump detection.The paper results show that nonlinear optics and ultrafast dynamics are influenced by the different CdTe quantum dots size which provide the theoretic foundation for the fabrication of quantum dots and the optical physics properties. |
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