https://scholars.lib.ntu.edu.tw/handle/123456789/31951
標題: | 一維奈米結構之二氧化銥和二氧化釕的拉曼散射和場
發射特性 Raman Scattering and Field Emission Properties of One-Dimensional Nanosized Structure of IrO2 and RuO2 |
作者: | 程仲良 Cheng, Chung-Liang |
關鍵字: | 二氧化釕;二氧化銥;拉曼散射;場發射;Field Emission;RuO2;IrO2;Raman Scattering | 公開日期: | 2004 | 摘要: | 摘 要 我們主要研究了過渡金屬氧化物材料的拉曼散射光譜和場發射性質,例如奈米管 (nanotubes) 或是奈米桿 (nanorods)。在奈米尺寸下,過渡金屬氧化物材料的大小、形狀以及較高的表面積對體積比 (surface-to-volume ratio) 都會影響本身的光學和電學性質,而不同於一般塊材 (bulk)的光學和電學性質。 我們報告了用有機金屬化學氣相沉積法所長成的IrO2 奈米管和RuO2奈米桿的Raman 光譜。發現IrO2奈米管的Raman訊號有紅移及半高寬變寬的波形出現,從奈米管和基板因晶格常數不匹配而生之應力方面,可以解釋Raman scattering所觀察到的結果,而RuO2奈米桿的Raman訊號則有紅移、半高寬變寬及不對稱的波形出現,則可從聲子侷限模型(phonon confinement model)可以解釋Raman scattering所觀察到的結果。 我們也報告了IrO2和RuO2奈米桿場發射性質,結果發現了其低的turn-on field,而在長時間的給電壓下,其電流穩定度相當高。且IrO2和RuO2擁有較高的導電性及較低的阻障屏璧,所以適合在低電場的情況下動作,則功率消耗會比較小,再加上本身是氧化物,不怕氧化,其真空度要求不需太高。所以由以上之特性可知IrO2和RuO2奈米桿適合做為長發射平面顯示器的場發射電極材料。 Abstract In this thesis, the Raman scattering and field-emission properties of one-dimensional transition-metal oxides like nanotubes or nanorods are reported. Due to their nanoscale size, shape and large surface-to-volume ratio, they behave quite differently from the bulk materials in the optical performance. They are presented as follows. I. Raman spectra and field emission of IrO2 nanorods Raman spectra and field emission measurement of IrO2 nanorods grown by metalorganic chemical vapor deposition (MOCVD) are reported. Red-shift and broadening of the linwidth of Raman spectra are observed. The peak positions and linewidth of the Raman features varied for IrO2 nanorods(tube-like) deposited on different substrate. These differences may indicate the existence of strain between IrO2 nanorods(tube-like) and the substrates. We also report on field-emission properties of conductive IrO2 nanorods. The unique geometrical features of IrO2 nanorods, including nanosized structure and self-assembled sharp tip, exhibit a strong effect on field enhancement (β=355), which result in a low threshold field (Eth=6.5 V/μm) defined at the beginning of emission. A low turn-on field for driving a current of 10 μA/cm2 is about 9.9 V/μm, which is comparable with the amorphous carbon. The potential of using IrO2 nanorods as an emitter material has been demonstrated. II. Raman spectra and field emission of RuO2 nanorods We report a detailed Raman Scattering study of RuO2 nanorods deposited on LiTaO3 substrate by MOCVD. Red-shift, broadening of linewidth and asymmetry of Raman spectra are observed. The lineshape of the Raman features are analyzed by the phonon confinement model. Phonon confinement effect was used to explain the experimental results of observed phonon modes. We also report on field-emission properties of conductive RuO2 nanorods. The unique geometrical features of RuO2 nanorods, including nanosized structure, exhibit a strong effect on field enhancement (β=1153), which result in a low threshold field (Eth=4.9 V/μm) defined at the beginning of emission. A low turn-on field for driving a current of 10 μA/cm2 is about 10.3 V/μm, which is comparable with amorphous carbon. The potential of using RuO2 nanorods as an emitter material has been demonstrated. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/54474 | 其他識別: | en-US |
顯示於: | 物理學系 |
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ntu-93-R90222047-1.pdf | 23.53 kB | Adobe PDF | 檢視/開啟 |
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