Absorption Cross-Section And Emission Cross-Section Of Ⅳ-Ⅵ Semiconductor Quantum Dots:PbSe In The Uv Glue Solution In The Near-Infrared Spectrum

Due to the constrained motion of their electrons and holes in three dimensions, the quantum dots (QDs) show a series of special properties, such as the quantum size effect, surface effect, the confined effect and macro quantum tunneling effect, which in turn leads to the discretization of the energy bands and spectrum. QDs of single size show obvious absorption peak in the absorption spectra. What’s more, higher photolumineous radiation than their bulk material and obvious emission peak are shown in the emission spectrum. QDs have a great application potential and a wide applications field, for example, QD laser, QD solar energy cells, and QD LED, etc. PbSe QDs, whose exciton Bohr radius is46nm, have strong quantum effect. And for4-7nm in diameter, their fluorescence emission peak at near-infrared band (1000～2000nm).The near infrared absorption spectra of three different diameter (4.5,5.0,5.6nm) of PbSe QDs are measured by spectrophotometer. The relationship between absorption peak wavelength and diameter of quantum dot can be summed up as an empirical formula. According to the Lambert Beer’s law, absorption cross-section peak, the corresponding absorption coefficient and their relationship with wavelength are determined in this paper. The results of experiment and calculation show a weak correlation between absorption cross section and the doping concentration. This weak correlation can be fitted by an exponential function. The range of the absorption cross section can be determine by study results. The fluorescence radiation spectra of quantum dots are measured by fluorescence spectrometer. We discover that the emission cross-section peak of the quantum dots also changes with the wavelength by using the Mc Cumber theory and absorption cross section. The effect of doping concentration on radiation section is fitted by an exponential function as well. This dissertation analyses the error causes throughout the experiment and estimates the errors. These section data of spectra have an important significance on designing gain devices and sensor doped by PbSe QDs.