The Theory Compution And Simulation Research Of Microcosmic Growth Pattern Of SiC Nanowire In The Initial Stage And The Effection Of Ni Liquid Drop’s Size On It

SiC 1-D nano materials shows excellent performance in many fields of science, such as in thermodynamics, electricity, magnetics, optoelectronics and so on. Therefore, the research and development which is related to SiC 1-D nano materials emerge in endlessly. In recent years, the research about SiC 1-D nano materials have become research focus in the field of nanometer materials. The microcosmic growth pattern of SiC nanowire have a prominent effect on its morphology, microstructure and atomic configuration, and these factors of nano materials decide its physical and chemical properties. As a result, it is significant to exploer the microcosmic growth pattern of SiC nanowire in the initial stage. In this paper, on the basis of our previous achievement, we have got the optimal catalyst and then employ the method of molecular dynamics simulation which is based on the first principles, we use the Materials Studio and SIESTA to simulation and research the microcosmic growth pattern of SiC nanowire in the initial stage, and the microcosmic growth pattern of SiC nanowire in the initial stage on the crystal face of Ni(111); In addition, we simulate and explore the relation between the size of catalyst and the microscopic growth pattern. The main achievements were as follows:Firstly, we use the Materials Studio to establish the model of Ni catalyst cluster, whose radius is 4?. Then we export its data of atomic coordinate and transport it into SIESTA to optimize the structure and calculate the energy of this model, and calculate the total energy of Ni catalyst cluster. After that, we adsorb active atoms on the cluster’s surface, and transport the atomic data to SIESTA to optimize the structure and calculate the energy. By calculating and comparing the adsorption energy, we can confirm some useful information, such as adsorption site, the species of adsorbed atoms and adsorption energy. By repeating the above-mentioned process and adsorb new active atoms on the surface of Ni catalyst cluster continuously, we can research the law of adsorption of these active atoms. By calculate and analyze the adsorb data, we can come to the conclusion that in the initial stage of the growth adsorption, the active C atom would prefer adsorb on the catalyst’s surface than active Si atom. With the adsorb process going on, the active C atoms form a coating layer on the surface of Ni catalyst cluster. When adsorb active atoms continuously, the active atom Si would prefer adsorbed on the coating layer than active C atom.Secondly, we research the growth pattern of SiC nanowire on the Ni(111) crystal face. We use the Materials Studio to establish the model of Ni(111) crystal face, and then adsorb an active atom on it. We use the Castep to optimize the structure and calculate the energy of the model of Ni(111) crystal face, and by compare the total energy and adsorption energy, we come to the conclusion that the active C atom adsorbed on the Ni(111) crystal face preferentially, then the active Si atom adsorb on the carbon atom and form an alternate growth pattern.Lastly, in order to research the effection of the cluster’s size on the growth mechanism, we use the Materials Studio to establish the model of Ni catalyst cluster, whose radius is 4?, 5?, 6?. We adsorb an active atom on the surface of the catalyst or inside of it, then export the atomic data to SIESTA to optimize the structure and calculate the energy. The results shows that the size of catalyst cluster have an obvious effection on the growth pattern. When the size of catalyst cluster is undersized, the active atom tend to adsorbed on the surface of the cluster to growth; when the the size of catalyst cluster increased, the growth pattern would change.