The Equivalent Optical Constants Of The Ordered Ag/AAO Nano-array Composite Structure

This dissertation firstly gives a brief introduction of the basic concepts, the developed history and the latest investigation about the nanomaterial and nanostructure, presents the great achievements in the study of synthesized technique and physical properties of the nano-array composites prepared by the AAO templates, sums up the many methods and difficulties in the area of determining the optical constants of thin films. Subsequently, the dissertation uses "The equivalent optical constants of the ordered Ag/AAO nano-array composite structure" as thesis, mostly describes the following work and results:1. The influence of thickness variation Ad on transmission of thin films has been studied, and then the optical transmission function of thin films is modified. So a simple method is established based on the envelope curves of the optical transmission spectrum at normal incidence, which is used for the accurate determination of the optical constants of the transparent films, but the simple method is not fit for the absorbing thin films. So we introduce optimization technique, define an evaluating function, and develop the simple method to determine the optical constants of the absorbing thin films effectively.2. The structural properties of AAO films are studied, and find that the AAO films are transparent thin films. So we make use of the simple method to determine the optical constants of the AAO films. It is found that the AAO films exhibit the optical features of a semiconductor with direct band gap of about 4.5 eV, and the optical constants of the AAO films strongly depend on anodic oxidation voltage, an important technologic parameter for preparation of AAO films. With the increasing of the anodic oxidation voltage, the optical constants including the refractive index, thickness and optical band gap of AAO films increase, and the extinction coefficient decrease.3. The Ag nano-particles are deposited into AAO template, and the Ag/AAO nano-array composite structure is synthesized. We measure the optical transmission spectrum of the Ag/AAO nano-array composite over the wavelength range 500 to 2700 run at normal incidence, and find it is an absorbing thin film. So we use the developed method to determine the equivalent refractive index n, equivalent extinction coefficient k, average equivalentthickness d and thickness variation Ad of the ordered Ag/AAO nano-array composite...