氧化鎵與氮化鎵相關之ㄧ維奈米結構製備與量測

Synthesis and Characterization of Ga2O3, Core-Shell Ga2O3-GaN, and GaN Nanowires

葉晏麟(Yan-Lin Yeh)

指導教授 ： 周立人

國立清華大學/工學院/材料科學工程學系/碩士(2006年)

摘要

鎵化物的半導體材料在工業界上廣泛的應用。隨著奈米科技的發展，一維奈米材料漸漸的被重視即於它獨特的物性及化性。本研究的第一部分在於低溫成長高密度且單晶的氧化鎵奈米線。以化學氣相沉積法利用鎵金屬在氧化矽基板上成長氧化鎵奈米線。其成長方式遵循V-L-S 機制。使用SEM，EDX，TEM分別去分析材料的表面形貌和成份分析以及結構特性。我們以不同的製程溫度去控制氧化鎵奈米線的線徑以及氧缺陷含量。由實驗的結果顯示，在較高的製程溫度當中，我們可以得到較大線徑以及較高含量氧缺陷的氧化鎵奈米線。在CL量測中，實驗發現氧化鎵奈米線激發放出藍光到綠光波長帶的電磁波，而此現象是由於存在氧化鎵奈米線中的氧缺陷及鎵缺陷所造成的。而在高氧缺陷的含量下會增加藍光波長的電磁波強度，使得在800℃下合成的氧化鎵奈米線的激發光譜相較於600℃下合成的氧化鎵奈米線會有藍位移的現象。在電性測量方面，氧化鎵奈米線會呈現N-type的半導體特性。
本研究的第二部分，氧化鎵奈米線做為合成氮化鎵奈米結構的模板並且在不同的氮化條件下得到不同的氮化鎵奈米結構，例如氮化鎵及氧化鎵的同軸奈米線，氮化鎵奈米線。而藉由將氮化鎵及氧化鎵的同軸奈米線在800℃下持溫兩小時並且在氫氣的氣氛下進行還原反應以去除氧化鎵，可以得到氮化鎵的奈米管。使用XRD和TEM去分析氮化鎵奈米結構的變化。最後CL 及場發射的量測用來探討結構的特性。

關鍵字

氧化鎵 ； 氮化鎵 ； 奈米線 ； 同軸奈米線

並列摘要

Ga-based semiconductors were extensive applied in the semiconductor industry. Along with the development of nanotechnology, one dimensional nanomaterials have been paid much attention due to their unique physical and chemical properties. In the first part of the experiment, molten Ga metal and silica were chosen as Ga source and substrate to approach the low temperature process. High density and single crystalline Ga2O3 nanowires were synthesized via vacuum annealing process at 400℃. The growth mechanism is obeyed the vapor-liquid-solid (VLS) method owing to the metal catalysts were found at the tip region of the nanowires. The surface morphology, compositions, and microstructures of Ga2O3 nanowires were characterized by SEM, EDX and TEM, respectively. Besides, the processing temperatures would significantly influence the diameter and the oxygen vacancy of Ga2O3 nanowires. From the measurement of cathodoluminescence (CL), the broad emission of the β-Ga2O3 nanowires was originated from various defects including oxygen and gallium vacancy. In this work, the blue emission of the β-Ga2O3 nanowires could be enhanced by the higher concentration of the oxygen vacancy. On the other hands, based on the result of the filed effect measurement, the Ga2O3 nanowires were considered as N-type semiconductors.
In the second part of the experiment, several GaN-based nanostrcuctures such as core-shell Ga2O3-GaN nanowires and GaN nanowires were achieved by using Ga2O3 nanowires as a template under different nitridation process. Furthermore, the GaN nanotube could be formed by annealing core-shell Ga2O3-GaN nanowires under H2 ambient at 800℃ for 2 hours in order to remove the inner Ga2O3. Finally, the results of the field-emission and the cathodoluminescence (CL) measurement were also presented.

並列關鍵字

Ga2O3 ； GaN ； Nanowire ； Core-Shell Nanowire

參考文獻

Chapter 1 Introduction

[01]Jurriaan Huskens

’’Integration of Top-Down and Bottom-Up Nanofabrication Schemes’’

’’Deterministic Addressing of Nanoscale Devices Assembled at Sublithographic Pitches’’

IEEE Transactions on Nanotechnology, 4, 6, (2005)