The Fabrication And Optical Properties Of Au Nanowire Arrays

One-dimensional gold nanomaterials received more and more attention because of their unique optical,electrical,catalytic properties, which exsit a huge potential application in new energy, optical information storage and biomedical fields. The research of gold nanowires has a very significant meaning for the function device of nanometer range put into practical. In this paper, highly ordered aluminum anodic oxide templates were prepared by the traditional two-step anodic oxidation of aluminum foils.One-dimensional gold nanowires arrays were fabricated in the aluminum anodic oxide templates by DC pulse electrochemical deposition,we also analysis and discussion the relevant factors that affect the crystal structure and optical properties of the nanowires:voltage and pH value.1、Highly ordered aluminum anodic oxide templates were fabricated in the0.3M oxalic acid electrolyte by two-step anodic oxidation of aluminum foils at the temperature of about0℃and the voltage of40V. The structure and morphology of AAO template were characterized by XRD and SEM,the results show that the AAO template is amorphous structure with60nm highly ordered hexagon pores,furthermore,we also discussed the growth mechanism of the template.2、The gold nanowire arrays were deposited into the porous aluminum oxide template by pulsed DC chemical electrodeposition.The influence of the applied voltage and pH value of electrolytes on the structure and magnetic properties of Au nanowire arrays has been studied, Single crystalline Au nanowire arrays with growing along the [200] direction have been obtained when the voltage at3V and the pH value is3after characterized by XRD, SEM,TEM,UV. At the same time,we also study the relation between the optical properties and voltage,pH value. It shows that with the deposition voltage increase, the absorption peak firstly blue-shift, then red-shift. When the voltage at a low range, hydrogen evolution reaction aggravates as the voltage increase, which will prevent gold ions from going into the template hole as a result the growth rate of the gold nanowires reduces, smaller aspect ratio of gold nanowires were got, leading to the absorption peak blue-shifted; When the voltage at a high range, the growth rate of the gold nanowires rises as the voltage increase,the impact of hydrogen evolution reaction become less important,so higher aspect ratio of gold nanowires were got. leading to the absorption peak red-shifted.Likewise, we find that the plasmon resonance absorption peak of the gold nanowires blue-shifted with the increase of the pH value, which because of the relation of the absorption peak position and the aspect ratio of the nanowires.The gold nanowires arrays fabricated in our experiments a will have a wide applications in the field of electronics, optics, sensors.etc.