利用簡單熱氣相沉積法成長之氧化銦奈米結構之相關特性研究

Abstract

在本篇論文中，主要是探討利用熱氣相沉積方法並且推測是藉由vapor-solid 與vapor-liquid-solid成長機制下所形成之氧化銦奈米結構相關特性的研究，在我的實驗中成功形成了三種奈米結構，分別為氧化氮銦奈米顆粒、氧化銦奈米串鏈、以及似水果枇杷狀的氧化銦奈米結構，在特性分析中，包含了結構與光學特性上的相關研究。結構及相關成分性的研究包含了掃描式電子顯微鏡圖像、高解析度穿透式電子顯微鏡圖像、能量散佈光譜、x光繞射圖…，在發光特性方面，所利用的是光激發螢光光譜的分析。 在第一部分的氧化氮銦奈米顆粒中，奈米顆粒推測是以VS的成長機制形成的八面體結構，以成長溫度在攝氏600度至900度形成各個尺寸從50奈米至1微米間的奈米顆粒，並可在能量散佈光譜中，驗證此奈米結構的存在成分，並在光激發螢光光譜中，可以看出此奈米顆粒的發光範圍可以涵蓋整個紅光波段。第二部分所形成的氧化銦奈米串鏈，亦是藉由類似方式所形成，僅別於利用直徑約20奈米的金奈米粒子先形成長於基板表面，形成奈米串鏈與基板的嫁接，而尺寸介於20奈米至100奈米間的奈米顆粒因而相連成串鏈，並且在研究熱退火過程中，發現熱退火對於此奈米結構在光學及結構特性上皆有改善。由於欲形成奈米柱狀的氧化銦奈米結構，因此以金奈米粒子最為觸媒，而形成最後一部分的枇杷狀氧化銦奈米結構，在高解析度穿透是顯微鏡圖像中，可以看出以VLS成長的證據，在此部分，我分別改變通入氧氣流量及成長溫度，來研究這兩變因對於結構及發光特性上的影響，結果發現在不同成長溫度下，對於發光波段之調變，有明顯助益，波長可從410奈米延伸至620奈米。

In this thesis, I mainly report on the growth and the characterizations of relevant Indium Oxide nanostructures via the suggested Vapor-Solid (VS) and Vapor-Liquid-Solid (VLS) mechanism by simple thermal vapor deposition. In my experiments, I have successfully synthesized three kinds of nanostructures: they are Indium-OxyNitride nanoparticles, Indium Oxide nanochains, and loquat-like Indium Oxide nanostructures sequentially. Moreover, I have characterized the nanostructures structurally and optically. The research on the nanostrucutres’ structures and the composition were carried out by Scanning Electron Microscope (SEM), High Resolution Transmission Electron Microscope (HRTEM), Energy Dispersive Spectroscopy (EDS), and X-ray Diffraction (XRD)…. On the optical emission part, I utilized Photoluminescence (PL) to investigate the emission wavelength. In the first section of my experiments, Indium-OxyNitride nanoparticles, they are octahedrons suggested to be formed via the VS mechanism dispersed on the Silicon substrate, ranging from 50 nm to 1 um in size grown from 600 degrees to 900 degrees in Celsius. The composition is also verified by the EDS apparently. The PL shows the emission wavelength spans the whole red region. In the second section, Indium Oxide nanochains were formed in the similar way; the difference lies only in utilizing 20 nm gold nanoparticles as the catalysts and the linkers for first nanoparticle growth on the top of the Silicon substrate. And then more and more nanoparticles connected to one another sequentially by the adhesion between each other. Besides, after annealing the as-grown samples, the structural and optical quality were both improved accordingly. Owing to the objective of forming Indium nanorods or nanowires, gold nanoparticles were still introduced as the catalysts for favoring the VLS mechanism to take place. As a result, the loquat-like nanostructures were formed. And the TEM images validated the growth via the VLS mechanism. In this section, I adjusted the Oxygen flow and the growth temperature separately as factors to examine the impact on their characteristics of structure and emission wavelength. Finally, it was found the growth temperature impacted obviously on wavelength tuning. The wavelength shifted from 410 nm to 620 nm as the growth temperature increased from 5000C to 9000C.