The Melting And Crystallization Behaviors Of Zn, Pb Nanowires In The Confinement Condition

With the rapid development of nanotechnology in the twenty-first century, the nanoelectronic components gradually play an important role in the stage of history. As the connecting wires and functional elements of nanoelectronic devices, the regulation and control of the internal crystal structure and properties for one-dimensional metallic nanowires has become the focus of attention. In this articles, Zn and Pb nanowires are fabricated by anodic aluminum oxide(AAO) template, which are melted at high-temperature. The different crystallization behaviors of melting nanowires are researched in the pore confinement effect of AAO with and without the induced electric field. This study provides important data for analysis crystallization mechanism of the liquid metal nanomaterials under the confinement effects in the future. The main contents are as follows:Firstly, a uniform size and highly ordered porous AAO template is prepared. The highly ordered AAO template is fabricated by the method of secondary anodic oxidation at 40 V direct-current voltage in 0.3 mol/L of oxalic acid solution. The high-quality one-dimensional Zn and Pb nanowires are prepared in the pores of AAO template by electrochemical deposition method. Then, the morphology and structure of the metal nanowires before and after the experiment are characterized and analyzed with transmission electron microscopy,X-ray diffraction and other equipments.Secondly, the crystallization behaviors of melting one-dimensional metallic nanowires are studied without the effect of electric field. At the temperature which is higher than the melting point of Zn and Pb nanowires respectively, the metallic nanowires are melted for long time,and then cooled to crystallize. Results of the characterization indicate that the melting Zn and Pb nanowires crystallize to become nanoparticles after long time of melting under the higher temperature. Meanwhile, with the increase of the melting temperature and time, the phenomenon of grain refiner becomes more obvious, relating with the clusters formation and decomposition of metallic nanowires during the melting. And Pb nanoparticles remain to keep a one-dimensional linear structure, while Zn nanoparticles eventually form a tubular structure,which is due to the characteristic of metal Zn thermal volatilization under high temperature.Finally, the crystallization behaviors of melting one-dimensional metallic nanowires are studied with the effect of electric field. The Zn and Pb nanowires remained one-dimensional morphology under lower melting temperature and short melting time, while some nodes are found in every nanowire applied with electric filed during the process of crystallization. With the increasing of electric field strength, the metal nanowires become particles gradually, and ultimately show the phenomenon of grain refiner. This indicates that the electric field plays an important role on the combination of metal atoms and the growth of nucleation.