Metal Anodic Alumina Membrane Microstructure And Optical Properties

In recent years, anodic alumina membrane(AAM), which forms unique structure when aluminum is anodized in acidic solution, has attracted an increasing interest. As a template, it has potential application in functional materials, such as optical components, magnetic materials, selective absorbing films etc. The functional application of AAM establishes another new way to develop functional materials.In this paper, optical properties of metal/ Al₂O₃ nano-array composite structure were systematically investigated after we investigated the existed domestic and foreign work about AAM in detail. This work could be very useful for fabricating new polarizer. The full text mainly includes six chapters given as follows.In the first chapter, we introduce the development of AAM and new functional materials which are made from AAM acting as host template. The main work of this paper is also introduced in this chapter.In the second chapter, the morphology and formative mechanism of AAM are discussed in detail. Then we introduce the physical properties and functional application of AAM.The third chapter narrates the preparation method and process of metal/Al₂O₃ nano-array composite structure and introduces research technique of their microstructure and optical properties. In this paper, their structure and morphology were measured by X-ray diffractometer and field-emission scanning electron microscope. Transmitted spectra and polarized properties were systematically investigated by spectrometers.The fourth and fifth chapters are the most important parts in this paper. In the fourth chapter, the microstructure and optical properties of Cu/Al₂O₃ nano-array composite structure were systematically investigated. XRD pattern indicats that Cu is preserved in the pores and Cu nanowires is formed along a preferential direction. SEM images indicate the ordered wire-grid structure of Cu nanowires, the diameter of which is consistent with that of the pores. Experimental results ofoptical properties show that (DCU-AI2O3 has good transmittance characteristic in near-IR waveband with average transmittance above 80%, indicating that Cu nanowires have good transmittance characteristic in near-IR waveband;(§) C11/AI2O3 exhibits good polarization in the range of 800-2000nm, and the polarization increase with the increasing deposition time.In the fifth chapter, we study the microstructure and optical properties of Ag/AhCb and CO/AI2O3 nano-array composite structure. For Ag/Al2O3, XRD reveals that Ag nanowires preserved in the pores are formed along a preferential direction, and Ag2O is also preserved in the pores of AAM. SEM image reveals that the diameter of the ordered wire-grid structure of Ag nanowires is about 20nm. Experimental results of optical properties indicate that ?the transmitted spectra of Ag/AbO3 prepared in different annealing temperature behave the same trend in mid-IR waveband, and the transmittance of Ag/Al2C>3 increases greatly with the increasing of annealing temperature, indicating that the ordered degree of the pores can be improved by annealing;?Ag/AbCb exhibits good polarization in the range of 900-2000nm and the annealing is useful for increasing the extinction ratio.For Co/Al2O3, XRD pattern reveals that the crystallographic structure of the Co nanowires preserved in the pores of AAM consist of a mixture of face-centered cubic(fcc) and hexagonal-close-packed(hcp) stacking. Optical measurement results indicate that ?the transmittance of CO/AI2O3 decreases with the increasing of electrodeposition time but increases with the pore widening time;?CO/AI2O3 has good polarization in near-IR waveband. Its extinction ratio increases with the increasing electrodeposition time, and as the pore widening time increases, its extinction ratio decreases firstly, then increases.In addition, the transmitted spectra of metal/Al2O3 in mid-IR waveband, influence on transmitted spectra of CU/AI2O3 caused by slit width and sample interval and incident angle effect on polarization of metal/AI2O3 were studied, and vast experimental data were obtained. Our work could be very useful fordesigning and fabricating metal/ AI2O3 polarizer and infrared absorbing materials.