利用熱蒸鍍法在氧化鋅中間層上製備高指向性氧化鋅奈米結構及特性研究

Growth and Characterization of Well-Aligned ZnO Nanostructures on ZnO Interlayer by Thermal Evaporation

李彥佑(Yen-You Li)

指導教授 ： 洪魏寬

國立臺北科技大學/電資學院/光電工程系研究所/碩士(2007年)

摘要

本論文主要在研究不同品質的中間層，對於準直奈米柱成長的影響。首先，我們對實驗中所用的兩種靶材做量測，發現兩種靶材中靶材A的晶粒較小，在實驗中也發現其材質較軟。之後，利用脈衝雷射蒸鍍法分別製作中間層；再使用高溫管爐分別再兩種中間層上進行結構成長。最後，透過場發射掃描式電子顯微鏡(FEDSEM)、穿透式電子顯微鏡(TEM)、X-ray繞射分析儀(XRD)，了解到晶粒較小的中間層，有利於準直奈米柱的成長。而晶粒較大者，可成長出六角尖錐結構。
我們觀察到在結構成長過程中，生成物的形態不但會隨著基板溫度不同而產生變化，而且中間層厚度也會影響其的形貌。經由SEM、TEM、XRD的測量結果可知，準直奈米柱與六角尖錐結構均為wurtize結構，且沿著[0001]方向成長。另外當成長溫度上升，準直奈米柱結構的線徑也會隨著小幅上升。成長溫度到達700℃後，奈米住之間有相互連接的趨勢，最後形成奈米牆。PL量測結果顯示準直氧化鋅奈米柱有兩個激發帶，分別為UV emission及green emission，我們計算green/UV emission比值與UV emission積分強度後發現，綠光的光強會隨著成長溫度上升而衰減；隨奈米柱線徑變小而增加。

關鍵字

氧化鋅奈米柱 ； 氧化鋅奈米尖椎 ； 熱蒸鍍法 ； 脈衝雷射蒸鍍法 ； 中間層

並列摘要

ZnO nanostructures were synthesized on a pulsed laser deposition (PLD) prepared undoped ZnO thin film (acting as an interlayer between the nanostructures and the c-plane sapphire substrate) by a catalyst-free thermal evaporation method. The effects of the crystallinity, thickness, and surface roughness of such an interlayer on the fabricated ZnO nanostructures were studied in this thesis. Scanning electron microscopy showed that high-density vertically well-aligned ZnO nanowire arrays or nanowire/nanowall structures can be grown on the interlayer with small grain domain, depending on the growth temperature. On the other hand, sharp hexagonal ZnO nanoawls were found to form on the interlayer with large grain domain. X-ray diffraction and transmission electron microscopy indicated that both the wires and walls crystallized in the wurtzite structure and grew in [0001] direction. The room-temperature photoluminescence spectra are composed of a strong UV band corresponding to the band-edge emission, and a weaker green band corresponding to the deep-level emissions. The UV peak shifts to higher energy as the averaged diameter of the nanowires decreases. The relative intensity of the green band decreases with increasing growth temperature and reduced interlayer thickness.

並列關鍵字

ZnO nanorods ； ZnO nanoawl ； Pulsed Laser Deposition (PLD)

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