脈衝雷射蒸鍍法製備氧化釓鋅薄膜的探討： 結構、光學與磁性研究

Abstract

我們是利用脈衝雷射沉積法製備摻雜釓的氧化鋅薄膜，X光繞射顯示樣品維持原有的晶體結構，但c軸晶格常數減小。因為薄膜的厚度在300nm以下，所以拉曼散射光譜只獲得微弱的訊號，樣品的能隙發光強度隨著摻雜濃度上升而下降，缺陷發光則隨釓濃度上升而增加，主要的缺陷有鋅錯位及鋅間隙，所有的樣品僅有Zn0.95Gd0.05O在室溫具有鐵磁性，其餘皆為順磁性。室溫(300K)的m-H曲線，只有x=0.051有磁滯曲線，在氧壓為3×10-1mbar及這樣的濃度下室溫是有鐵磁性。In this thesis, Gadolinium (Gd)-doped ZnO (Zn1-xGdxO) thin films were grown on c-sapphire by pulsed-laser deposition. The nominal Gd concentration is between 0% and 20%. The XRD patterns show that there is no secondary phase, and c-lattice constant decreases with increasing Gd density. Only one weak ZnO oscillation mode was observed from Raman spectroscopy because the thickness of the thin films is sm-aller than 300nm. Photoluminescence spectroscopy at different temperatures showed a slight decrease in band gap and increase in defect emissions as Gd concentration increases. The major defects are zinc vacancy and interstitial zinc. The room temperature m-H curves show that there is only hysteresis loop for 5.1% Gd, the rest show only paramagnetism.