Study On The Preparation And Optical Properties Of The Transition Metal Doped And Pure ZnSe One-dimensional Nanostructure

As a branch of diluted magnetic semiconductors,transition metal ion doped ?-? semiconductors are important.And the research techniques of nano-photonics can explore the microscopic interactions of magnetic ion and magnetic ion,magnetic ion and host material.This is a promising area for ZnSe 1D nanostructures.Also,ZnSe 1D nanostructure is a potential component of micro-device,but it's easy to form various defects.As a result,it's necessary to study the influence of various growth conditions on the nanostructure systematically.In this paper,we doped the Fe³⁺and Cr³⁺ions into ZnSe lattice successfully by CVD method.And we also prepared ZnSe 1D nanostructure by Au-catalytic,Sn-catalytic CVD method and hydrothermal method.At the same time,the morphology was characterized by SEM and optical microscope.The elementary composition was analyzed by EDS.The micro-Raman and photoluminescence spectrum were used to study the optical properties as well as the internal microscopic mechanism.The specific research results are just as follows:(1)ZnSe nanostructure preparation with various methodsZnSe 1D nanostructures were prepared successfully by CVD(Au-catalysis,Sn-catalysis)and hydrothermal method.It is found that the preparation of Au-catalytic nanostructures need higher growth temperature,and the influence of sedimentary position,temperature,time is obvious.The nanostructures shape types are abundant with high yield,while it's easy to form various defects.Compared with Au catalysts,Sn-catalytic method has advantages such as low growth temperature,low energy cost and excellent luminous performance,while the disadvantage is low yield.At the same time,it has some of the same characteristics with Au-catalytic method such as the shorter preparation time,the simple operation method,etc.The toxic ethylene diamine was used as template agent in hydrothermal method and the nanobelt size reaches micron level with the introduction of organic matter in nanobelts.At the same time,the optical performance is not good and this method needs longer preparation time.(2)the preparation of Fe³⁺-doped ZnSe nanobeltsFe³⁺-doped ZnSe nanobelts(NBs)were grown by facile CVD method.The morphology and the element composition confirms that the Fe³⁺ions have been incorporated into ZnSe NBs successfully.The micro-Raman spectra demonstrate that as-prepared NBs are zinc blend structure.And the Raman spectra of Fe³⁺-doped NBs were compared with those of pure and Fe²⁺-doped reference samples.The former with the enhanced 2LO mode intensity,stronger LO mode redshift and larger intensity ratio of LO/TO mode,as well as the lower acoustic phonon mode intensity,confirms the better crystallization and the stronger electron-phonon coupling with Fe³⁺incorporation.The emission of single Fe³⁺ion,assigned to the ⁴T₁?⁶A₁ transition,was observed at about570nm.And the increasing Fe³⁺ions concentration caused the formation of Fe-Fe coupled pairs in the lattice,which emit light at about 530-555nm for antiferromagnetic coupling near the stacking faults,and at about 620-670nm for ferromagnetic coupling.(3)the preparation of Cr³⁺-doped ZnSe nanobeltsThe Cr³⁺-doped ZnSe nanobelts were also prepared by CVD method.The morphology and optical characterization verified they possess better crystallization and optical waveguide than pure ones.The Raman spectra indicated that as-prepared NBs are zinc blend structure.At the same time,the near band edge shows two luminescent peaks close to each other,one is attributed to the bound exciton and the other to EMP.Defect related luminescence may be caused by the intrashell transition of Cr³⁺or may be related to the defects.And there are small oscillation peaks on the defect related emission band.In a word,the effect of ion doping into zinc selenide nanostructures is very significant.The research techniques of nano-photonics can explore the microscopic composition and structure of nanomaterials or the microscopic interactions between different elementary excitation.It shows the micro process of optical properties and it's the groundwork for further device design especially for iron doped system in which the magnetic coupling state of Fe ion can be detected by micro-spectrum detection.