氧化鋅與氧化鎂鋅奈米結構成長及特性研究

Growth and Characterization of ZnO and MgZnO Nanostructures

邱士峰(Si-Fong 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(2008年)

摘要

本研究分為三個部份，第一部份為純氧化鋅奈米柱之成長。利用脈衝雷射蒸鍍法先製作厚度30nm氧化鋅緩衝層，然後利用氣相傳輸法在c-plane sapphire基板上成長出高方向性的氧化鋅奈米柱，觀察表面結構，氧化鋅奈米柱的直徑相當均勻，高度約為1μm，成長結晶方向為(0002)，並且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。
第二部份是利用此氧化鋅奈米柱，使用高溫爐作第二階段製程，使用鎂粉當做蒸發源，藉著鎂蒸發源(source)多寡，使結構產生變化。當source比例依序增大時，會首先在氧化鋅奈米柱外圍會鍍上一層氧化鎂層，形成core-ZnO/shell-MgO的異質結構，如果source增多時，在核殼構造的中間會產生一結晶品質差的MgxZnO1-x層，根據計算，x值約為0.4左右，為氧化鎂鋅混合相，最後，當source再增加時，氧化鋅奈米柱會因為鋅蒸發消失而變成中空的氧化鎂管。
第三部份則是使用脈衝雷射蒸鍍法作為鍍鎂的第二階段製程，發現也有core-ZnO/shell-MgO的異質結構，跟高溫爐製程方法比較，發現方向性、結晶品質跟發光效率都較好，奈米柱表面則較為粗糙。

關鍵字

奈米柱 ； 氧化鋅 ； 氧化鎂鋅 ； 奈米管

並列摘要

Aligned nanorods or nanotubes with similar diameter are ideal candidate material for fabricating nanodevices. In addition, the formation of heterostrucure in nanorods is essential for their potential applications in nanoelectronic and photonic devices. Here we demonstrate that well-aligned ZnO nanorods, ZnO/MgZnO core-shell nanorods, and Mg(Zn)O nanotubes can be successfully synthesized via catalyst-free vapor phase transport combined with pulse laser deposition (PLD) method.
The thesis consists of three 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 ~20 nm and length of ~1μm. Room-temperature photoluminescence spectra of the samples showed only a strong band-edge emission, indicating the high crystalline quality. The vertically aligned ZnO nanorods were used as templated for the synthesis of nanorods heterostructures.
In the second part, ZnO/MgZnO heterstructure nanorods were fabricated using a thermal evaporation procedure, in which the Mg powder was used as the source material and the aforementioned ZnO nanorods slice was used as the substrate. We found that different nanotructures can obtained by varying the amount of Mg source. Smaller amount of Mg resulted in ZnO/MgO core-shell nanorods. However, as the source material was increased, an MgxZn1-xO (with~0.4) interlayer formed between the ZnO core and the MgO shell. Further increasing the Mg amount finally led to the formation of MgO nanotubes.
In the third part, aligned ZnO/Mgo core-shell nanorods were synthesized by PLD of MgO onto the ZnO nanorod template. Compared with the similar nanostructure produced by thermal evaporation process (as described in the second part), the PLD produced ZnO/MgO nanorods had rougher surfaces, while exhibited better quality in alignment, crystallinity, and luminescence efficiency.

並列關鍵字

nanorods ； ZnO ； MgZnO ； nanotubes

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