具高透光率之氧化鋅鎂鎵透明導電薄膜之光電特性研究

Investigations of Optoelectronic Properties of Transparent Conductive Ga-doped MgxZn1-xO Films

陳威谷(Wei-Ku Chen)

指導教授 ： 劉維昇

元智大學/電機通訊學院/光電工程學系/碩士(2012年)

摘要

近年來透明導電氧化物的應用已備受重視，因其具有高透光率與高導電率兩項重要特性，使其極適合廣泛應用於各類光電產品及顯示器之中。目前已廣泛使用之透明導電氧化物，如：氧化銦錫(ITO)，因其材料內之銦元素屬於稀有元素，且價格昂貴，同時氧化銦錫在高溫操作下並不穩定，因此本計畫便提出以氧化鋅鎂及其複合材料取代氧化銦錫之可能性，並對其做深入光電特性研究。
氧化鋅鎂(Magnesium doped Zinc Oxide)所擁有之高能隙將增加材料電阻率，故將加入鎵元素摻雜於氧化鋅鎂薄膜中，冀改善薄膜導電性。本論文將使用射頻磁控濺鍍法沈積氧化鋅鎂鎵(Ga-doped MgxZn1-xO)薄膜，並控制鎂摻雜含量多寡，以調整材料能隙延伸薄膜高透光率至較氧化銦錫至更短波長處。此外經由退火後之取代行為，鎵原子將取代鋅原子使得載子濃度提升，造成 Burstiein-Moss 效應，預期可使薄膜除了呈現高導電特性外，且還有更短波長的吸收邊界。實驗結果顯示將以X-ray繞射(X-ray Diffractometer，XRD)系統觀察薄膜結晶特性、以霍爾量測系統(Hall measurement)量測薄膜電性、以紫外光/可見光分光光譜儀(UV/VIS Spectrophotometer)系統進行光學性能分析、以X光光電子能譜儀(X-ray photoelectron spectroscopy，XPS)量測薄膜成分以及光激發光螢光(photoluminescence，PL)系統觀察薄膜品質，最後以各種合理的解釋敘述量測及所觀察到的現象。

關鍵字

透明導電氧化物 ； 鎵摻雜氧化鋅鎂 ； 射頻磁控濺鍍 ； X光繞射 ； 熱退火 ； 氧缺陷

並列摘要

More and more attentions have been placed on the applications of transparent conductive oxides (TCOs) in recent years for their transmittance and conductivity that make TCOs highly suitable for photo-electronic products and display monitors. A good example of TCOs that have been widely used is indium tin oxide (ITO). However, the indium in the oxide is very rare and thus expensive, and ITO is highly unstable when worked with at high temperature. For these reasons, a proposal is made in this study to investigate the possibility of replacing ITO with magnesium-doped zinc oxide and its composite materials and their photo-electric characteristics.
Magnesium-doped zinc oxide (Mg-doped ZnO) has a high energy gap that will enhance the resistivity of material, and thus gallium (Ga) will be added to the Mg-doped ZnO thin films to improve the thin film conductivity. Ga-doped MgxZn1-xO thin film will be deposited using RF magnetron sputter, and the amount of Mg doping will be carefully controlled to adjust the energy gap of material and in turn extend the high transmittance of thin film to a wavelength much shorter than that of ITO. In addition, Zn atoms will be replaced with Ga atoms using the replacing after annealing, thus increasing the carrier concentration and creating the Burstein-Moss effect. It is expected to not only make the thin film high conductive, but also enable the absorbing boundary condition at shorter wavelength. For the experiment result, X-ray diffractometer (XRD) will be used for observation of the crystalline characteristics of the thin film, Hall measurement for measurement of electric properties of the thin film, UV/VIS spectrophotometer for optical performance analysis, X-ray photoelectron spectroscopy (XPS) for measurement of composition of thin film and photoluminescence (PL) for observation of the thin film quality. Finally, the phenomena measured and observed will be described using various reasonable explanations.

並列關鍵字

X-ray diffraction ； Thermal Annealing ； Oxygen Vacancies ； Transparent Conducting Oxide ； Ga-doped MgxZn1-xO ； Radio-Frequency Magnetron Sputtering

參考文獻

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