Preparation And Characterization Of AIN And GaN Nano-materials

Information functional materials such asⅢ-Ⅴsemiconductor materials have been the hot topic of semiconductors research field in recent years.Ⅲgroup nitride attracts much interest due to their novel performance.Developing new synthesis method,expanding into new synthesis system,preparing new structures,investigating new functions and applications are the foreland research topics.Synthesis ofⅢnitrides is a base of information functional materials research.On the basis of comprehensive and thorough investigation of literatures concerning the developments ofⅢgroup nitride nanomaterials synthesis and applications,in this dissertation,new chemical methods of synthesis were explored.Gallium nitride and aluminum nitride were synthesized by using pureⅢgroup melt as reactants in a stainless steel autoclave.The main contents can be summarized as follows:1.Aluminum nitride was produced by using aluminum powder and hydrazine hydrochloride as reactants in 500-650℃in a stainless-steel autoclave.X-ray powder diffraction(XRD) pattern results indicated that the product was hexagonal AlN with a lattice constant a=3.10(?),c=5.02(?).These are close to those of the reported values (JCPDS card No.25-1133,a=3.11(?),c=4.98(?)).Transmission electron microscopy (TEM) photographs showed the morphology of prepared AlN was mixture of nanorods and nano-particles.On the basis of many experiments,we also deduced possible mechanism of aluminum nitride formation.2.Gallium nitride was synthesized by using gallium metal and sodium amide as reactants in 350-550℃in a stainless-steel autoclave.X-ray powder diffraction(XRD) pattern results indicated that the product was hexagonal GaN with a lattice constant a=3.1951(?),c=5.1832(?).These are close to those of the reported values(JCPDS card No.74-0243,a=3.195(?),c=50182(?)).Test results of SAED and HRTEM further demonstrated the prepared GaN had wurtzite structure.According to the experimental results of the analysis,we found reaction temperature was related to the crystallinity of GaN.Sharp diffraction peaks were gained with the elevated temperature.Heating rate impacted the GaN nano-particle size.Faster heating rate resulted in the large size of the final products.On the basis of above experiment,iodine and benzene were added as reatants and solvent,getting zinc blende GaN.Removal of benzene,using the above method,we also got GaN materials.X-ray powder diffraction(XRD) pattern results indicated that the product was hexagonal GaN with high purity.Therefore,we inferred that benzene played an important role in the synthesis of zinc blende GaN.