| Anodic alumina oxide (AAO) templates have diverse applications in the fabrication of nanostructured materials and photonic devices due to their hexagonally ordered pore arrangement, anti-erosion, fine transparency and mechanical properties. The fabrication of AAO templates is quite simple and of low cost, and ordered AAO templates with inter-pore distances from tens to hundreds of nanometers can be obtained by controlling the anodizing conditions, which make them quite popular among scientific and business world. This dissertation focused on the fabrication and growing mechanism of highly ordered AAO templates by anodization, as well as the optics based on AAO templates.In this paper, we give a brief introduction about the concept, history of nano science and technology, and the main apparatus used to characterize nanostructured materials. Then, the major development of research about AAO templates is discussed in details in the paper. In order to present a full and accurate knowledge about AAO templates, my paper also includes the structure models, formation mechanisms, fabrication techniques, and main applications.Three kinds of AAO templates were prepared by almuinmun aodizing in three given electrolytes (oxalic,phosphoric and sulfuricacid solution, respectively) with two-step method. It was studied influence of experimental conditions,such as the electrolyte, temperature, the oxidation voltage, current,time, as well as annealing condition, etc.,on the thickness, aperture and degree of order of AAO templates were studied. SEM and AFM were employed to characterize the different stages of AAO tempelates. We made use of computer to record the current-time curves of oxidation process. Combining with the influence of current on the templates, we discussed the origin of the self-assembled pores of AAO templates.In addition, the relationships of pore diameter and anodizing voltage, thickness of films and anodizing time, thickness of films and anodizing voltage were shown. We annealed AAO templates at different temperature and gas, in order to find out effect of annealing on the AAO templates appearance and optics properties. AAO templates were all amorphous that were fabricated in oxalic acid and annealed at low temperature. When the annealing temperature reached 800℃,AAO templates became to crystalline.At the temperature over 1100℃,AAO templates transformed toα-Al2O3.And much growing mechanism of AAO templates was directly validated by experiment. We successfully fabricated the highly-ordered AAO templates, employing the way of double-electrode, and resolved many questions about the fabrication of AAO templates using single-electrode. While the area of AAO templates was enhanced using double-electrode.Three peaks were found in absorption spectrum of AAO templates at 203,250 and 275nm,the peaks of 203 and 275nm were due to F centers (oxygen vacancy with two electrons) and F+ centers (oxygen vacancy with only one electron), respectively.The peak of 250nm was produced by oxalate ions, which was caused by the process of fabrication. At the same time, a reasonable explanation was given about the disappearing of the peaks of 250 and 275nm, when the anneal temperature was raised. By studying absorption spectrum of AAO templates, which were made in different anodic oxide time and voltage, we found the effect of red-shifted of AAO templates absorption band-edge. And by researching the photoluminescence (PL) properties and luminescence mechanism of AAO templates, prepared in sulfuric, oxalic and phosphoric acid solution respectively, we knew that there was a strong PL band among 330-650nm, The analysis revealed that the luminescence of 420nm of AAO templates originated from F+ centers, and the 470nm maybe originate from F centers. However, the PL peak of 370nm was from oxalate ions, the same time, there was a new peak of 535nm originated from unknown reasons. |
PDF Full Text Request