• 學位論文

鐵鈀金三元鐵磁性記憶合金塊材研究

本研究探討熱鍛、熱輥壓與熱機處理後Fe70Pd30-XAuX(X=3，5，7)塊材試片其微結構、相變化溫度、磁性質、磁伸縮值、形狀記憶效應、織構的變化。 用熱輥壓製備AuX(X=0，3，5，7)塊材試片，發現添加Au可改善試片抗氧化性與塑性變形能力，減少熱輥壓產生的裂紋。在冷輥過程中發現Au5(1)- TMT2試片具有177.33%的長度變化，初步推測原因為試片母相結構為非序化 fcc結構，添加Au更增加傾向類似Au的巨大塑性變形能力，其中機制待更進一步研究。 熱機處理後的AuX-TMT1(X=3，5，7)塊材試片中Au5(1)-TMT1、Au7-TMT1在室溫下結構為熱彈性fct麻田散相，顯示添加Au可提升相變化溫度，以添加5% Au效果最好可提升Ms約30K，得到最低晶格常數比值(c/a)為0.93。各試片降至液態氦溫度4K仍不會產生非熱彈性bct麻田散相，顯示添加Au能有效抑制bct生成。 室溫飽和磁化量以Au3-TMT1最高，Au5(1)-TMT1最低，矯頑磁場變化趨勢則相反;磁伸縮值上，θ=90o時的最大磁伸縮值隨Au含量增加而上升。 形狀記憶效應方面，成份相同的Au5試片，形狀回復率隨試片厚度增加而升高。不同成份的Fe70Pd(30-x)AuX試片在近似厚度下，各塊材試片形狀記憶回復率大致相同。

• 學位論文

電鍍成長鎳金多層一維奈米結構於氧化鋁模板之製程

Abstract Fabrication of one-dimensional nanowires has been researched for many years. Furthermore the multilayered nanowires were also synthesized to investigate their fundamental properties for various applications. By use of Anodic Alumina Oxide (AAO) as template, the nanowires synthesized by electrochemical method could be fabricated in large scale with low cost and high throughput. In this work, Ni/Au multilayered nanowires were synthesized by dual-bath method. Ni layers were deposited by electrodeposition and Au layers were produced by Galvanic replacement. The structures were characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM), and their magnetic properties were characterized by Vibrating Sample Magnetometer (VSM). The results shown that a sharp Ni/Au interface and regular structures with nanowire diameter of ca. 265 nm is obtained. The diffraction pattern of Ni layer indicated that the nanowires is polycrystalline structures. Magnetic measurement by VSM showed that easy-magnetic directions are dominated by shape anisotropy of Ni layers. Diffusion behavior between Ni/Au layers were also studied by annealing at high temperatures. X-Ray diffractometer (XRD) was used to identify the phases after annealing. The results showed that NiAu metastable phase appeared at 650 oC accompanying with NiO phase. The NiO is due to oxidation of Ni at high temperature during venting the chamber. Annealing at 750 oC caused agglomeration of Au atoms and the XRD cannot detect NiAu phase. Besides, the NiAu phase tends to separate at 750 oC. Magnetic measurement also showed a decrease of coercive field as the annealing temperature rises.

• 學位論文

銻基相變化記憶材料之開發與探索

The purpose of this dissertation is to study Sb-rich binary materials extended for applications in phase-change memory (PCM). Studied characteristics include thin-film properties and memory-cells performance of Ga-Sb alloys and Sb-C materials, and the crystallization behavior of ultra-thin phase-change films. Finally, we propose an alloy design method to reasonably predict the ultra-fast crystallization behavior. The Sb-rich, Ga-Sb films (91 to 77 at% Sb) exhibit a high crystallization temperature (Tx, 183 to 261 °C), and high activation energy of crystallization (Ea, 2.3 ~ 8.3 eV), resulting in good thermal stability. The kinetic exponent is smaller than 1.5 at Sb < 86 at%, denoting that the crystallization mechanism is one-dimensional crystal-growth from nuclei. The temperature corresponding to 10-year data-retention (T10Y), is 180 °C for Ga19Sb81, and 148 °C for Ga16Sb84, respectively. A steep resistance drop during crystallization arises mainly from the sharp increase in carrier- concentration with p-type conduction. Ga16Sb84 memory cells demonstrate SET- RESET switching at pulse-width 10 ns and durability >1E5 cycles. According to phase-diagrams, carbon and antimony are immiscible and not forming Sb-carbides. However, carbon addition is able to stabilize amorphous Sb phase. Raman and XPS spectra depict formation of C-Sb bonds in Sb-C films, which renders long-range ordering of amorphous Sb to higher crystallization temperatures. Thermal stability of amorphous Sb-C films is precipitously enhanced to show Tx of 256 and 262 °C, Ea of 3.14 and 3.52 eV, at 8 and 13 at% C, respectively. Structure of C-Sb films after full crystallization belongs to Sb phase. The T10Y of 87 at% Sb films is 168 °C. Memory test-cells made of Sb92C8 film show reversible switching at pulse-width 100 ns. It also shows the typical snapback behavior by applying I-sweep mode at the threshold voltage of 1.5 V, and full-SET at 2.1 V (snapback). As decreasing film thickness of Ga16Sb84 films from 10 to 3 nm, the exponential increase in crystallization temperature (from 221 to 249 °C), electrical resistance ratio (1E3 to 1E5), and the stabilized Sb(Ga) phase (after annealing at 500 °C in 10nm-film) are attributed to increased specific interface-energies and inhomogeneous interfacial strain at the interfaces. This phenomenon is also observed in ultra-thin Sb films. We propose an isothermal-heating transformation curve and a continuous-heating transformation curve, which extrapolate from Arrhenius’ and Kissinger’s plots, to predict the crystallization behavior of Sb-rich binary material under very fast ramp rate. It also provides a useful method to design suitable compositions with good thermal stability, fast crystallization speed, and good data retention ability

• 學位論文

SrTiO3/TiO2奈米複合材料應用於染料敏化太陽能電池之研究

在染料敏化太陽能電池(Dye-Sensitized Solar cells, DSSC)內部的各個反應界面中，電子的再結合反應為造成電池效率無法提升的主要原因之一。具有異質接面之複合材料，因其互相匹配之能帶位置，能有效幫助電子的傳遞，抑制電子的再結合反應，提高電池的轉換效率。本實驗利用TiO2(commercial anatase TiO2與P25)與Sr(OH)2，以水熱法在120˚C下反應不同時間，合成具有不同SrTiO3含量之SrTiO3/TiO2奈米粉末，並以此複合材料當做工作電極，應用於DSSC。在DSSC的表現上，開路電壓大幅提升，但短路電流卻下降，造成電池之轉換效率無法提升。雖然SrTiO3/TiO2可有效抑制電子的再結合，但因其具有較高之平帶電位，可能會影響電子注入的驅動力，減緩電子注入的速度，造成光電流無法提升。本實驗將近一步討論染料的吸附、電子注入效率與收集電子的能力，詳細探討影響DSSC表現之各種因素。

• 學位論文

奈米碳管矩陣結構之低電場調控表面張力

本論文分成兩個部分，第一部分利用疏水性的陣列奈米碳管作為電濕潤的固體表面，藉由施加平行電壓產生電雙層及電泳，造成固-氣間表面張力上升和固-液間表面張力下降，導致液滴與界面的接觸角下降，達到電濕潤的效果。 論文第二部分則是探討不同離子濃度對電濕潤的影響，藉著施加相同電壓時，不同離子濃度的情況下，液滴的接觸角會產生不同變化，因此，本節主要討論藉由離子的存在與否與濃度變化，來控制液體的電濕潤現象。

• 學位論文

空孔與顆粒缺陷在矽晶圓對界面中行為之研究

本研究藉由動態刀刃法觀察矽晶圓對中不同種類缺陷於界面之行為特性，探討晶圓對界面上之空孔缺陷及人工製作的顆粒缺陷與刀刃受力關係及差異，建立界面缺陷行為的可能機制，以及討論不同熱處理溫度與矽晶圓對上不同位置對晶圓對界面強度與局部接合強度之影響與關係。 根據矽晶圓對之動態刀刃法分析結果，刀刃所承受之推壓力隨熱處理溫度與插刀時間增加而增加。當刀刃裂口接近未經熱處理晶圓對的空孔缺陷時，缺陷發生前進移動而非預期的與裂口快速連結，且空孔缺陷移動距離會受刀刃已運動距離長短影響，刀刃所承受之推壓力隨插刀的時間而增加，推測與氫鍵密度增加有關，而當空孔缺陷與裂口連結瞬間刀刃所承受之推壓力無明顯變化。至於熱處理後晶圓對的空孔缺陷及顆粒缺陷行為，乃如預期的與刀刃裂口快速連結，連結瞬間，因釋放晶圓之彎曲彈性能可觀察到刀刃承受之推壓力值明顯減少。

• 學位論文

Fracture-induced concentric semi-circular patterns on the surface of polymer films

A new type of fracture induced structuring (FIS), which shows concentric semi-circular wrinkles with periodic spatial wavelength. A complementary set of nonsymmetrical concentric surface wrinkling of polymer is formed on the fractured surface of a polymer thin film which is sandwiched between two rigid plates. We examined several parameters such as thickness of polymer film, kind of polymer, substrate thickness and separating rate of the sandwich structure to affect fracture induced structure. The effect of material properties of polymer thin films on the surface modulation of FIS is also studied using gamma-irradiation. The ring-type surface wrinkling of the polymeric films is considered to be generated by the presence of the compressive residual surface stress which can be described by the apparent surface traction. The polymer resist (mr-8030E) and polystyrene were used to investigate the phenomenon of ring-type surface wrinkling. Using the spatial wavelength of the surface wrinkling and the initial film thickness of polymer thin film, the apparent surface traction which is a combination of surface energy and residual surface stress was found as a function of the film thickness. The magnitude of the apparent surface stress decreased with decreasing film thickness and approached a constant value.

• 學位論文

AlxCo1.5CrFeNi1.5Tiy與Al0.3CrFe1.5MnNi0.5高熵合金之微結構與磨耗行為

本研究的第一部分中，設計了不同Al跟Ti含量的AlxCo1.5CrFeNi1.5Tiy系列高熵合金，並針對其組成相與微結構做研究。文中探討此系列合金之黏著磨耗行為與機制，並與常見的耐磨鋼材，SUJ2軸承鋼及SKH51高速鋼做比較。結果顯示Al跟Ti的含量會顯著地影響合金的組成相與微結構，特別是其中堅硬的η-(Ni, Co)3Ti相之數量與形貌。Al0.2Co1.5CrFeNi1.5Ti合金在相近的硬度表現下，其磨耗阻抗至少比常見的耐磨鋼材好一倍以上。這些高熵合金之所以會有如此傑出的磨耗阻抗主要是因為其優異的抗氧化性與抗高溫軟化性質。 在第二部分中，本研究使用Al0.3CrFe1.5MnNi0.5高熵合金，展示了一種利用在靠近表層區域局部析出的表面硬化處理方法。這種表面析出硬化法製程簡單，只需要在大氣下進行一般的時效處理，並且適用於複雜形狀的物體。實驗的結果顯示，經過此表面硬化的Al0.3CrFe1.5MnNi0.5高熵合金，其磨耗阻抗至少增加了百分之五十，並且只有些許的彎曲韌性損失。跟常見的SUJ2軸承鋼與SKD61熱作工具鋼比起來，此表面硬化處裡過的Al0.3CrFe1.5MnNi0.5合金有著更好的機械性質組合。

• 學位論文

金-氧化鎵一維異質結構奈米線的電漿子光學性質與光電性質研究

This dissertation aims to explore fundamental plasmonic and optoelectronic properties and possible photonic applications for one-dimensional gold-in-Ga2O3 peapod and core-shell nanowires. Single-crystalline gold-in-Ga2O3 nanowires have been systematically synthesized by a bottom-up method and a wide range characterized of their peculiar properties. The diameters and interparticle distances of gold peas, core diameters and core lengths of gold rods, were tuned during material growth in a controlled manner. Morphology, microstructure and composition of as-grown nanowires were characterized through scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM) analyses. Light-scattering properties and light-interference phenomena of individual gold-in-Ga2O3 nanowires were investigated by dark-field optical microscopy (OM). Light-emission properties of gold-in-Ga2O3 nanowires were studied by photoluminescence (PL) and electroluminescence (EL) spectroscopy. Surface potential distributions of single gold-in-Ga2O3 nanowires illuminated with a green light source of 532 nm in wavelength were revealed by Kelvin probe force microscopy (KPFM) and optical microscopy under ambient conditions with exceptional spatial and energy resolution. The major peaks in measured scattering spectra were suggested to result from plasmonic resonance of the gold nanopeas and nanorods embedded in the Ga2O3 nanowires when comparing with simulation data from Mie and Gans calculations. The cladding Ga2O3 dielectric layer was considered as a surrounding medium for localized plasmon resonance on gold nanostructures and played a key role in light-scattering properties. Light-interference spectra of single gold-in-Ga2O3 peapod nanowires excited with a white light source in p-polarization demonstrated their applicability of being plasmonic nano-resonators. During the optical resonance, the Ga2O3 shell provided a wave-guiding medium for surface plasmon wave and scattered light of short propagation length bouncing back and forth within the nanowire. Photoluminescence and electroluminescence studies of gold-in-Ga2O3 nanowires indicated that luminescence of outer single-crystalline Ga2O3 matrix further excites localized plasmon resonance in inner gold nanostructures as the nanowire is properly optically-excited. Surface potential images of single gold-in-Ga2O3 nanowires under the illumination of selective light source presented direct evidence for energy flow from applied electromagnetic wave to gold-in-Ga2O3 complex nanostructures and quantified the induced electric potential fluctuations in the nanowires; which helped depict a detailed profile of the physical mechanism for the nanowires working at plasmon frequencies. The investigation results of plasmonic and optoelectronic properties of one-dimensional gold-in-Ga2O3 peapod and core-shell nanowires would be applied to the optimum design of related nano-photonic devices and further extend to similar kinds of complex nanowires for enhanced performance, eventually function as an integrated element in optical nano-circuits.

• 學位論文

多孔性金屬離子交換沸石去除氣態分子污染物之研究

本論文主要探討多孔性沸石在去除氣態分子污染物所發生的現象，研究主題有一般沸石與離子交換沸石對污染物之吸附、脫附和對二甲基硫(DMS)進行輔助氧化的效果及對SO2之常溫氧化探討。經吸附測試結果，以沸石Y-30對IPA及PGME之效果最佳，起始去除率可達99.0%以上， 飽和吸附力則分別可達5.0及18.0 wt%以上。以TPD-Mass進行IPA脫附溫度測試，其脫附峰值溫度約在120℃。在去除SO2方面，以4Ag-4Mn /ZSM-5進行去除SO2測試，起始去除能力為99.0%以上，飽和吸附量可達28.7 wt%，對NH3的起始去除率在99.0%以上，飽和吸附量可達1.7 wt% 。 在去除DMS方面，使用吸附及輔助氧化系統進行測試。在吸附方面，對低濃度DMS之起始去除率可達95.0%以上，處理量可達1.0 wt%以上。在輔助氧化方面，氧化觸媒搭配臭氧，可將DMS進行一階、二階及三階之氧化，在氧化觸媒表面轉化成DMSO、DMSO2及SO2。銀-錳離子交換ZSM-5沸石(Ag-Mn/ZSM-5)可在高濕度環境下有效去除DMS，同時探討氣相中水分子對不同型態金屬離子交換沸石吸附 DMS的影響。以FT-IR吸收峰變化及TPD-Mass脫附曲線確認水分子對金屬離子交換沸石吸附DMS活性點的影響。 另外在輔助氧化方面，進行多種離子交換沸石對DMS之活性及穩定性測試，結果以雙金屬銀-錳離子交換沸石效果最佳，可在130℃的條件下將DMS完全去除，並探討觸媒中金屬離子在反應中所扮演的功能，發現銀離子可有效吸附DMS，而氧化錳組成可協助將DMS氧化成高階氧化產物及SO2。 最後探討以各種離子交換沸石處理SO2的效果，並以XPS分析觸媒表面金屬之鍵能差異並搭配TPD分析結果，解析單一及雙金屬離子交換沸石在吸附SO2及反應本質的差異，用以解釋雙金屬離子交換沸石可有效將氣相中SO2吸附去除並進一步轉化成H2SO3 或氧化成 H2SO4的原因。