The Synthesis Of InN And SnO₂ Semiconductor Nanomaterials And Their Properties Studies

Nanomaterials,due to their small size effect,quantum size effect,macroscopic quantum tunneling effect and so on,have unique physical and chemical properties that are distinctly different from bulk materials.Thus,nanomaterials have been widely used in various applications.It is well known that the physical and chemical properties of nanomaterials depend on their morphology,size and other microstructure.Therefore,in order to explore the unique properties and implement the application of nanomaterials,the controllable preparation of nanomaterials with different morphology and phases has recently become more and more of interest in the field of material science.The semiconductor nanomaterial,that is represented by indium nitride and tin dioxide,as a new semiconductor material which is nonexistent in nature,have wide application prospect in field of optoelectronic devices and functional materials for their advantages of excellent photoelectric properties,steady chemical property and high sensitivity.Among them,the optical absorption edge of the indium nitride nanomaterial is about 0.7 e V at room temperature.And it will be possible to tune them to any wavelength from ultraviolet to infrared simply by synthesizing specific Inx Ga1-xN alloy.Therefore,the indium nitride nanomaterial has extremely excellent optical properties,and will provide a new direction for the development of the optoelectronic devices.In this paper,indium nitride and tin dioxide nanomaterials with special morphology were synthesized by using a simple chemical vapor deposition?CVD?.And the growth mechanisms of samples with special morphology were analyzed,the factors that affect the morphology of the samples were also studied in detail.And the optical properties as well as the effecting factors have been the focus in this paper.The main work and results obtained from the researches of this paper are summarized as follows:1.Three-dimensional InN micromaterials,namely InN microspheres and split octahedron-like microstructures,were successfully synthesized by using chemical vapor deposition?CVD?.The growth mechanism of these InN microstructures with special morphologies was discussed in detail.The observations suggest that the formation of the InN microsphere and the split octahedron-like microstructure could be attributed to the different self-organization processes.2.In order to reveal the reason that two kinds of microstructures were prepared in the different regions of the same substrate,we discussed the factors that affect the morphology of the samples in CVD method,and designed a series of comparative experiments.The results reveal that the two different self-organization processes could be induced by the difference in nitrogen concentration.3.The optical properties of the two kinds of InN samples were discussed and compared.Both of the two InN samples show a similar broad yellow-orange emission band,and the PL emission bands of the InN samples were centered at ².17 e V,which is far bigger than the theoretical value of the intrinsic bandgap of InN nanomaterials?⁰.7 e V?.The potential factors that could lead to the larger band-gap energy than the theoretical value is the nitrogen-rich stoichiometry.4.A lot of tin dioxide nanomaterials with various morphologies were prepared by chemical vapor deposition?CVD?,including: octahedral,branch-like,rime-like,and anomalous spherical tin dioxide nanostructure.And The growth mechanism of these Sn O₂ nanostructures was discussed in detail.In order to explore the experimental parameters,such as the carrier gas,reaction temperature and the oxygen flow,influence to the morphology of the samples,a series of contrast experiments were carried out.