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http://ir.hust.edu.tw/dspace/handle/310993100/2253
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| 題名: | 以溶膠凝膠法製作Zn1-xYxO與 Zn1-xFexO 透明薄膜特性之研究
Investigation on the characteristics of Zn1-xYxO and Zn1-xFexOtransparent films fabricated by Sol-gel method |
| 作者: | 張閔欽 |
| 貢獻者: | 電機工程研究所 |
| 關鍵詞: | 氧化鋅
溶膠凝膠
光學特性
光致發光
電性
可變範圍躍遷
磁性 |
| 日期: | 2009-07
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| 上傳時間: | 2011-05-23T06:20:20Z
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| 摘要: | 本文主要研究利用溶膠凝膠法結合旋轉塗佈技術製備在玻璃基板上的摻釔氧化鋅（Zn1-xYxO）及摻鐵氧化鋅（Zn1-xFexO）透明薄膜，分別探討在不同燒結溫度及不同摻雜元素的比例對氧化鋅薄膜特性的影響。製備的薄膜經由 X-ray繞射結果分析其晶格結構及晶粒大小，結果顯示製備的Zn1-xYxO、Zn1-xFexO薄膜結構皆為纖鋅礦結構，且結晶方向皆有很高的 c 軸取向，另外也沒有觀察到二次相的產生。樣本經由X-ray繞射的半高寬數值利用Debye-Scherrer’s equation計算出晶粒大小作比較，顯示因摻雜物與氧化鋅的離子半徑的不同，會影響薄膜的結晶情況，同時也有影響其後續各項特性。利用掃描式電子顯微鏡觀察薄膜表面形態，樣本表面顯示為多孔性的奈米結晶形態，且沒有觀察到有摻雜元素的群集。但特別的是，摻釔的樣本薄膜表面型態有五邊形或是六邊形之鏈狀紋路，並有很高的再現性。利用紫外光/可見光分光光譜儀（UV-VIS-NIR spectrometers）量測光穿透率，Zn1-xYxO與Zn1-xFexO薄膜在可見光波長範圍光穿透率皆可達到80 %以上。利用（αhυ）2對光子能量圖配合外插法求出能隙，結果顯示出摻雜的比例對薄膜的能隙有ㄧ定的影響。所有樣本經由螢光光譜量測，在紫外光區皆可以觀察到一個明顯的放射峰，且有摻雜的樣本會在綠光（約520 nm）及橘光區（約600 nm）各觀察到一個明顯的放射峰。隨著摻雜濃度的增加，綠光及橘光放射峰有明顯的增強；且紫外光區放射峰也隨著摻雜濃度的增加而減弱。薄膜進行電性量測，藉由 Arrhenius plot，樣本顯示在室溫時，薄膜主要的載子傳導機制為熱活化能形式(activation type)，在低溫時主要的載子傳導機制為可變範圍躍遷（variablerange hopping，VRH）。最後對薄膜經磁性量測，發現所有樣本皆具有磁性，且磁矩隨著摻雜的比例增加而增大。
In this study, the Zn1-xYxO and Zn1-xFexO transparent nanocrystalline thin films had grown on glass substrates by sol-gel with spin coating technique. The structural, surface morphology, optical, electrical and magnetic properties of the transparent thin films annealed at various temperature and different doping concentration had been investigated.
By X-ray diffraction measurement, all transparent thin films have the wurtzite structure with a preferential orientation along the c-axis, and no secondary phase has been found. By using the Debye-Scherrer’s equation, the grain size of the films reduces as the increase of doping concentration. The grain size and the corresponding characteristics of the films are affected by different ionic radius of the doped ion.
By the Scanning Electron Microscopy images, the morphology of the films reveals porous granular surface for all sample. There is not any doped-element cluster have been found. Especially, the pentagon or hexagon veins are observed on the Zn1-xYxO thin films.
The optical transmittance spectra of the films have been measured by using the UV-VIS-NIR spectrometers. The average optical transmittance value of Zn1-xYxO and Zn1-xFexO thin films were more than 80% in the visible range. From the plot of (νυ)2 versus photon energy of the films, the energy gaps of the films is reduced as the increase of doping concentration.
Photoluminescence spectra of the films deposited with various doped concentrate had been measured. All samples have three kinds of emission peaks at UV, green and yellow emission regions. For the pure ZnO thin film, the UV emission peak is equal to the ZnO energy gap, which intensity decrease with the increase of doped concentration. And the green and yellow emission peak intensity was increase with increase doped concentration.
Temperature dependence of resistance of all samples reveals the semiconductor transport behavior. At high temperature region, the transport mechanism can be fitted well with the behavior of activation type. At the low temperature region, the resistance can be fitted well with the behavior of variable range hopping, ρ(T) =ρnexp[(T*/T)n]. From the measurement of hysteresis, all samples exhibit ferromagnetism. The results suggest that ferromagnetism of the films is highly correlated with the oxygen vacancy. |
| 描述: | 指導教授：楊尚霖教授 |
| 顯示於類別: | [電機工程系(含碩士班)] 學位論文
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