Controllable Synthesis And Optical Properties Of Micron And Nanoscale Ⅲ-Ⅴ Phosphides And Nitrides

The goal of this dissertation is to explore novel synthetic methods and routes to synthesizeâ…¢-â…¤semiconductor phosphides and nitrides micro and nano-scale materials with controlled structures and various novel morphologies.The optical properties of products with different morphologies are studied carefully.InP hollow nanospheres could be obtained using template method or Ostwald ripening route in ethanolamine-water binary solution.Wurtzite GaN taper rods were synthesized using NaNH₂ and the as-synthesized precursor GaOOH prismatic rods as reactants in a stainless steel autoclave.Rhombohedral BN were synthesized on a large scale in a stainless steel autoclave using B₂O₃ and NaNH₂ as reactants.The details are summarized as follows:1.InP hollow spheres were obtained by using In spheres as templates.The In/InP core-shell nanospheres were synthesized using InCl₃·4H₂O,P₄ and NaBH₄ as starting materials in ethanolamine-water binary solution.At the first step,In³⁺ was reduced to liquid metallic In by NaBH₄.A amount of InP was formed via the reaction of the reduced liquid metallic In and liquid P₄.The newly formed InP coated on the outer surfaces of aggregated metallic In particles.When P₄ was exhausted,In/InP core-shell structure was formed.Then when removing the unreacted In by treatment with dilute HCl,the inner In disappeared and InP hollow nanospheres were formed.So we think that liquid metallic In was served as hard template in the process of formation of InP hollow nanospheres.The sizes,shell thicknesses and morphologies of InP could be controlled by varying the reaction conditions.In detail,when yellow phosphorus was insufficiency,In/InP core-shell nanospheres were synthesized and after acid treatment InP hollow nanospheres were obtained.The sizes and shell thicknesses of InP hollow nanospheres could be controlled by varying the quantities of InCl₃·4H₂O and P₄. When yellow phosphorus was abundant,InP solid spheres were prepared without acid treatment.InP solid nanospheres and flowerlike architectures could be obtained by changing the volume ratio of EA/H₂O.The above results of research have been published in Journal of Alloys and Compounds.InP hollow nanospheres were solvothermally synthesized in EA-H₂O binary solution using Ostwald ripening route.Furthermore,the similar route has been extended to prepare other metal phosphides hollow nanospheres including Cd₃P₂,Cu₃P and Sn₄P₃.This synthesis method is simple and it will likely provide an alternative synthetic route to other metal phosphides.The above results of research have been published in Journal of nanoscience and nanotechnology.The optical properties of InP hollow nanospheres were investigated by the photoluminescence spectra.The InP products prepared in our experiments can emit blue light,which is different from the previous reports and increases the potential applications of InP nanomaterial.One possible cause for this blueshift is the compressive stress that results from lattice distortion of these ethanolamine-capping nanoparticles.2.Wurtzite GaN taper rods assembled from highly oriented nanoparticles were synthesized using NaNH₂ and the as-synthesized precursor GaOOH prismatic rods as reactants in a stainless steel autoclave.The formation of GaN taper rods involves two steps.First,the orthorhombic GaOOH prismatic rods decomposed into rhombohedral Ga₂O₃ prismatic rods.Then the Ga₂O₃ prismatic rods transformed into GaN taper rods through a high-temperature reaction process without destroying the 1D framework. The GaN taper rods displayed luminescence emission in the blue-violet region,which maybe related to crystal defects.The above results of research have been published in Journal of Solid State Chemistry.3.Rhombohedral BN with regular triangular shapes were synthesized on a large scale in a stainless steel autoclave using B₂O₃ and NaNH₂ as reactants at 600℃.The weight and phase of the r-BN triangular nanoplates prepared in our experiment have no change below 800℃.These reveal that the as-prepared BN has excellent thermal stability and anti-oxidation property,which may be helpful for high-temperature electro-optical applications of r-BN material.The above results of research have been published in Journal of Solid State Chemistry.