氧化鋁包覆氧化鋅奈米核殼結構成長與特性

Growth and characterization of ZnO-Al2O3 core/shell nanostructures

邱奕豪(Yi-Hao Chiu)

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(2009年)

https://doi.org/10.6841/NTUT.2009.00167

摘要

實驗製程分為三個部份：
第一部份利用脈衝雷射蒸鍍法(Pulsed Laser deposition ,PLD) 在c-plane sapphire 基板上先製作氧化鋅緩衝層，厚度約為77nm。
第二部份是利用在利用氣相傳輸法使用氧化鋅粉當做蒸發源在c-plane sapphire 基板上成長出高方向性的氧化鋅奈米柱，而成長出的氧化鋅奈米柱由掃描式電子顯微鏡(Scanning Electron Microscopy ,SEM)觀測直徑相當均勻，高度約為600nm，X光繞射儀(X-ray diffraction ,XRD)量測峰值強度為17.2∘且成長結晶方向為(0002)，並且經由光激螢光光譜(photoluminescence, PL)測知奈米柱的發光強度與結晶品質相當好，也沒有發現缺陷而造成的可見光。
第三部份則是使用脈衝雷射蒸鍍法作為鍍氧化鋁的第三階段製程，在氧化鋅奈米柱外圍會鍍上一層氧化鋁層，發現有core-ZnO/shell-Al2O3 的異質結構，藉由改變蒸鍍時間2.5min到10min可有效的控制氧化鋁的厚度從5nm至8nm，而經由穿透式電子顯微鏡(Transmission Electron Microscopy ,TEM)量測可發現外層氧化鋁部分有非晶、多晶的現象。

關鍵字

脈衝雷射蒸鍍法 ； 氧化鋅 ； 氧化鋁

並列摘要

With the growing interest in ZnO nanowire-based devices, the focus of research is now shifting towards more complex nanowire assemblies like ZnO/polymer compound structures and nanowire-based core–shell structures. Core–shell nano-heterostructures formed by the growth of crystalline overlays on nanostructures offer enhanced emission efficiency, high conductor layer or dielectric layer, which are important for various applications .
Here we demonstrate that well-aligned ZnO nanorods, ZnO/Al2O3 core-shell nanorods can be successfully synthesized via catalyst-free vapor phase transport combined with pulsed laser deposition (PLD) method.
The thesis consists of two parts. Fist, vertically aligned ZnO nanorods were grown on a PLD-predeposited ZnO thin film via a simple thermal evaporation and vapor transport process. These ZnO nanorods were quite uniform with a diameter of ~40 nm and length of ~600nm. Room-temperature photoluminescence spectra of the samples showed only a strong band-edge emission, indicating the high crystalline quality of the nanorods. The vertically aligned ZnO nanorods were used as templated for the synthesis of core/shell heterostructures.
In the second part, ZnO/Al2O3 core–shell nanorods were fabricated by depositing thin Al2O3 films on the ZnO nanorods using PLD. The thickness of Al2O3 shell can be controlled by changing the laser pulse numbers. To further analyze the core–shell nanorods structure, TEM characterization was performed.
High resolution TEM (HRTEM) characterization of the nanorods revealed that the core is wurtzite structured ZnO. The measured interplanar distance of 0.26 nm corresponds to the ZnO(0002) planes, indicating that the ZnO nanorods grew preferentially along the c-axis direction. The shell layers consist of amorphours and polycrystalline, identified as α-Al2O3.

並列關鍵字

Pulsed Laser deposition ； ZnO ； Al2O3

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