Study On Synthesis At Low Temperature And Photoelectroncharacteristics Of Mn:ZnSe Quantum Dots

Mn:ZnSe and ZnSe QDs were prepared at room temperature in the water solution,and L-cys was chosen as ligand.X-ray diffraction,scanning electron microscopy,transmission electron microscopy,Fourier transform infrared spectroscopy and Raman spectroscopy were used to analyze the effects of doping on the composition,microstructure and morphology of quantum dots;the UV-visible absorption spectrum,steady state Surface photovoltage and transient surface photovoltage was used to detect the photoelectric properties such as separation,transmission,and recombination of carriers in quantum dots.The band structure and density of states of ZnSe before and after doping were calculated by using the CASTEP module of Materials Studio software.Mn was selected as the doping element to adjust the photoelectron characteristics of the quantum dots.And the concentration variable(molar ratio Mn: Se = 1:5,1:10,1:20,1:30,1:40,1:50)And the time variables(doping times are 0 min,20 min,40 min,60 min,80 min,100 min respectively)was set to explore the optimal doping conditions.The results show that the Mn:ZnSe quantum dots are cubic sphalerite structures,and the crystals tend to grow on the(220)plane during growth.The prepared quantum dots are spheres having a particle diameter of 2-3 nm.The Fourier transform infrared spectroscopy and Raman spectroscopy show that the sample is a core-shell structure of ZnSe/ZnS/ligand.And surface photovoltage and the surface photovoltage detection under the applied electricfield show that the obtained quantum dots have p-type photovoltaic characteristics,and the doping of Mn not only expands the response range,but also improves the photoelectricity responsiveness of quantum dots.Transient photovoltage detection shows that Mn doping greatly increases the separation rate and diffusion distance of photogenerated carriers.The band structure and skewed density of ZnSe,Mn doping,S doping and Mn and S co-doped sphalerite ZnSe were calculated by CASTEP module of Materials Studio software.The simulation results show that S doping makes the system band gap wider,while Mn doping makes the band gap narrow.