溶膠-凝膠法製備鈦酸鑭鉛薄膜之晶格動力學與摻鉺鈦酸鑭鉛薄膜之光學特性研究

Abstract

此次的工作是利用拉曼光譜研究Pb1-xLaxTiO3薄膜的晶格動力學，並研究摻鉺Pb0.8La0.2TiO3薄膜螢光發光機制，所有的樣品都是利用溶膠-凝膠法製備。在Pb1-xLaxTiO3(PLT)系統中，我們認為在分析的過程中必須考慮晶格中因鈦原子位移所造成的影響。經由分析，發現當x從0.00增加到0.20，我們可以觀察到材料LO和TO模的分裂情形，並且也觀察到和Pb1-xLaxTiO3 (PST)系統一樣的遞減LO-TO分裂趨勢，而有效電荷的改變是造成這種趨勢的主要機制。此外，摻鉺Pb0.8La0.2TiO3薄膜的綠色螢光發光效率和鉺離子濃度、燒結溫度的關係主要是由樣品的結晶性和樣品中鉺離子和鉺離子的距離所主控的，我們的研究指出樣品在摻鉺3莫耳百分比和結晶性最佳的情況下具有最大的發光效率。

This work makes a study of the lattice dynamics of Pb1-xLaxTiO3 thin films by Raman spectroscopy, and the luminescence mechanism of erbium-doped Pb0.8La0.2TiO3 films. All samples were prepared by sol-gel method. In the Pb1-xLaxTiO3 (PLT) system, we found that considering Ti-disorder induced background is necessary during the analysis of Raman spectra. The giant splitting of longitudinal optical (LO) and transverse optical (TO) phonon modes has been found while x increased from 0.00 upward 0.20. The decreasing LO-TO splitting, which is the same with Pb1-xLaxTiO3 (PST) system, was observed in Pb1-xLaxTiO3 (PLT) system. The change of effective charge to the LO-TO splitting is the dominant mechanism in PLT. In addition, the dependence of green luminescence efficiency on Er+3 concentration and sintering temperature in the Er-doped Pb0.8La0.2TiO3 thin films is governed by crystallinity and ion-ion interaction. Our study indicates that the observed green emission reaches maximum at 3 mol % Er dopant concentration with the best crystallinity.