Preparation And Photoelectric Properties Of One-dimensional Al-doped ZnO Nanomaterials

In recent years,the optoelectronic device industry and the optoelectronic research field are developing rapidly.The optical properties of nanomaterials make them have a good research prospect and are widely used in the optical field.Because of the optical and electrical properties of ZnO,as well as its chemical and mechanical stability,ZnO nanomaterials have gradually replaced ITO materials in research and production.Studies have shown that doping Al,Ga,In and other group III elements In ZnO can significantly improve the crystal structure,optical properties and electrical conductivity of the material,and the carrier concentration of ZnO can be controlled.Among many ZnO doped materials,al-doped Zinc Oxide(AZO)is the most representative.It not only has high transmittance and low resistivity in the visible region,but also has very stable chemical properties,which can be stable in the hydrogen ion environment.In this paper,the preparation method of chemical vapor deposition(CVD)is used to realize the controllable one-dimensional synthesis of AZO nanomaterials.By optimizing the experimental scheme,the effects of different experimental conditions on the morphology,composition and structure of the material were summarized,and the structure-activity relationship of the material was analyzed.The linear and nonlinear optical properties of AZO nanomaterials are further studied.Firstly,ZnO and AZO samples with different morphologies were prepared by CVD,then AZO nanomaterials synthesized under different experimental conditions were characterized basically.The experimental results show that the size of ZnO and AZO nanowires can be influenced by the regulation of gas velocity and substrate distance.The gas velocity is large,the substrate distance is small,and the size of nanowires is large.The morphology and size of AZO nanomaterials can be influenced by controlling gas velocity,substrate distance and doping ratio of source materials.Three kinds of AZO nanomaterials with different morphologies were prepared.Secondly,the linear optical properties of AZO nanomaterials were studied,and their spectral characteristics and luminescence mechanism were analyzed.Ultraviolet-visible absorption spectrum(UV-Vis)shows that the ultraviolet absorption peak of AZO nanomaterials is at 375 nm.The results of photoluminescence(PL)spectroscopy showed that the AZO nanomaterials exhibited an ultraviolet peak centered at 382 nm and a visible peak near 550 nm,respectively.These two emission peaks were derived from free exciton recombination and defect level transition.And the experimental results show that with the increase of Al doping content,the ultraviolet absorption peak has a clear blue shift,which is due to the increase in the optical band gap of ZnO nanomaterials after Al doping.In addition,the laser intensity and test temperature were changed to analyze the PL spectral characteristics of AZO nanomaterials.The results show that the intensity of the UV emission peak increases linearly with the excitation intensity,but decreases with increasing temperature.Finally,Z-scan technology was used to study AZO nanomaterials and analyze the nonlinear optical properties of AZO samples under different morphology and different laser conditions.The nonlinear absorption coefficients of nanowires,nanobelts and nanoplance-cone were obtained.The size of the relationship:nanobelts>nanowires>nanoplance-cone.Moreover,under the condition of femtosecond laser,the hole opening z-scan of three AZO nanomaterials showed Reverse Saturable Absorption.Under the condition of femtosecond laser,the nano-diameter decreases continuously,and the nonlinear absorption coefficient decreases continuously.