藉由光致變化效應研究矽酸鉍晶體的雜質能階及其對光折變效應的影響

Abstract

本論文將研究釕、鈷、鋨等元素的摻雜及鈷和鋁元素共同摻雜對矽酸鉍(Bi12SiO20)晶體的光折變效應之影響。基於實際的應用考量，我們希望光折變晶體能在較便宜的半導體雷射波長範圍內作記錄，目前同屬於硫化物結構的鈦酸鉍晶體(Bi12TiO20)已能在長波長790nm下記錄光柵，但是因為鈦酸鉍晶體的長晶技術無法做大體積的塊材，因此大大地限制了其應用，因此我們希望能做成大體積塊材的矽酸鉍晶體也能在近紅外光區亦能記錄光柵，為此，我們選擇了幾種元素作為摻雜，希望能夠將矽酸鉍晶體的感光波長往長波長方向移動，我們將藉由一系列量測來跟能階結構的理論相對照，並探討繞射效率對時間的變化關係，來了解這幾種元素的摻雜對於矽酸鉍晶體內光折變效應所產生的影響。

In this thesis, we investigate the influence of Ru, Co, Os, Co+Al doping on Bi12SiO20 crystals . Because the semiconductor laser is cheaper than other lasers, We hope we can use this laser to do record. Now the Bi12TiO20 crystals can use wavelength 790nm to do record but it is very hard to increase the volume, this reason limits it’s application. However, Bi12SiO20 crystals don’t have this limit, we want to use them to do record at long wavelength. In order to let them be more sensitive at long wavelength we dope some elements in these crystals. Then we use a series of methods to find their impurity levels and measure the change of diffraction efficiency by time. By this way we can understand the effect of these dopants in Bi12SiO20 crystals.