本研究以熱壁式的常壓化學氣相沈積法，合成長碳化矽奈米線，在總流量50 sccm以及反應溫度在1100℃，甲烷與矽基板當作反應來源，氫氣當載流氣體並且稀釋甲烷氣體濃度到適當濃度，並利用二茂鐵放在載舟的上風處當作催化劑，其目的在探討其粗糙度也就是表面形態對於生長碳化矽奈米線凝核與成長的關係。
另一方面因為有許多文獻提出成長碳化矽奈米線，反應經常會有關於SiO蒸氣的探討，所以實驗設計以不同的方式在矽晶圓，鍍上一層二氧化矽薄膜，去探討有關於在反應中SiO蒸氣存在之必要性，期望藉由上述兩種變因，以此種低溫、容易且低成本的製程，長出品質好、純度高及發光效率佳的碳化矽奈米線。
結果發現不論以何種粗糙度的基板，皆可生成大量的奈米線，然而研磨基板的顆粒大小(砂紙號數的不同)，會產生不同直徑的奈米線，由實驗可得知以400#砂紙研磨出的奈米線其直徑較小，因為它所造成的凹洞剛好適合金屬液滴沈積形成奈米線，其他較細砂紙研磨所生長之奈米線，因為其金屬液滴太小不符合奈米線的成長，導致成核處變大，也因此使直徑變大；另外的二氧化矽鍍膜，可以直接長出奈米線不經由表面處理，不同的二氧化矽鍍膜會對奈米線長出的形貌有很大的差異，二氧化矽的鍍膜有三種製作方法：旋轉塗佈法、濕式氧化法以及RF磁控濺鍍法，其中以旋轉塗佈法的二氧化矽最容易生成碳化矽奈米線，因為此結構之融化點與氣化點較低，所以很容易就可以生成SiO的蒸氣，另外如果二氧化矽以石英的形式實驗，其產物只有非晶質的碳雜質，因其有高溫的熱穩定性，則不容易使SiO的蒸氣產生，因此適當的二氧化矽鍍層是可以促進生成碳化奈米線的。
實驗所生成的奈米線，經由TEM以及拉曼的分析，其中有兩種結構一為實心且筆直的碳化矽奈米線，其成長晶面為 (111) 面，但是以TEM所觀察之奈米線的直徑多為10~30nm左右，比起SEM下觀察所得的直徑40~50nm，有著20~30nm的差異，根據文獻所提到其外層有可能是以一層非晶質的二氧化矽所包覆，所形成的同芯雙層結構(core shell structure)；另一種奈米線是彎曲的多層奈米碳管，可看出其中空的結構，其直徑大約在10~50nm。
最後我們利用陰極激發光譜 (CL) 去測定長出奈米線的發光性質，發現其受電子激發後放射光譜皆會往藍光方向移動，推斷應是奈米級尺寸所發生的能隙調變 (bandgap modification) 的效應造成，導致碳化矽奈米線由3C-SiC的550nm (2.26eV) 位移到450nm附近，也就是能隙調變到2.70eV左右，此外以不同砂紙號數所產生的粗細不同之奈米線，會造成其移動量有差異，因此以奈米線粗細來製作可調式發光器是有可能的。

In this study, we synthesized silicon carbide nanowires (SiCNWs) by catalystic thermal chemical vapor deposition technique. Methane was used as the reaction gas along with hydrogen as carrier and dilution of methane gas. Silicon wafer was used as the substrate. Ferrocene was used as a catalyst and was placed in a boat upstream before Si substrate kept in isothermal zone of a hot wall chemical vapor deposition (HWCVD) reactor at atmospheric pressure. The total flow rate of gases (CH4+H2) was maintained 50 sccm and the growth temperature was 1100 ℃. The main objective of the study is to understand the influence of surface roughness of the substrate created by using different grade sand papers to produce SiCNWs, and to study how these surface modifications affect the nucleation and growth kinetics of nanowires.
Because there are many literature reports which describe the growth of SiCNWs usually relate to the SiO vapor, so keeping this in mind we designed experiments to grow different silicon dioxide film on the silicon wafer, to investigate the role of SiO in the reaction process. Thus the second major objective of the study is to understand the influence of presence of SiO on the growth characteristics of SiCNWs. This was expected to be a low temperature, low cost and easier method to produces high quality SiCNWs possessing high purity and excellent luminance efficiency.
The results of this study showed that regardless of roughness of the substrate, we could produce a large number of nanowires. However, the particle size of the abrasive sand paper (number of different sandpaper) resulted in nanowires with different number density and quality. Moreover, the diameter of the nanowies grown on scratched substrate (with 400 grade sandpaper) is smaller, because it caused the pits which are suitable just fit in size to accommodate the metal droplets formed nanowires. The pits made by other smaller grade sandpaper do not meet the size requirement for metal droplets fitting in them leads to larger size droplets resulted formation of nanowires having larger in diameter. In addition to this, we found that the silicon dioxide coating can grow nanowires directly without other surface treatments. It is also found that the morphology of the SiCNWs is different as obtained from the different silicon dioxide coating. The silicon dioxide coating on Si substrate was done by three different methods; thermal chemical vapor deposition, RF magnetron sputtering and spin coating. Silicon dioxide coating by spin-coating method produced the best growth of SiCNWs, as this structure of the gasification and melting point are relative low, so it is easy to generate SiO steam. On the other hand, in case of quartz substrate formation of amorphous carbon impurity was found. Because of its high temperature stability, SiO steam is not easy to produce. Therefore use of silicon dioxide coating can promote the growth of SiCNWs.
The SiCNWs obtained from the experiment were examined by Raman and TEM analysis. TEM results revealed formation of solid and straight SiCNWs, their growth of crystal face is (111) face and the diameter observed by TEM of the nanowires is in the range of 10~30nm. The diameter of nanowires measured by TEM is found to be larger than that observed by SEM is 40~50 nm. This is in accordance with the literature, as it is possible that the outer layer of nanowires is surrounded by amorphous silicon dioxide. This structure is knows as core shell structure. The other nanostructures formed in this process include multiwall carbon nanotubes (MWCNTs), and curved nanowires which can be seen to have hollow structure. The diameter of MWCNTs is in the range of 10~50 nm.
Finally, we used Cathodoluminescence (CL) to detect the luminescence of the nanowires, found after the electronic excited, they all are found to be shifting to the Blue range. The blue shift in case of SiCNWs is more as compared to SiCNWs with larger diameter. The SiCNWs from the bulk 3C-SiC of 550 nm (2.26eV) shift to around 450 nm, which is equal to the energy gap modulation (~ 2.70 eV). In addition the SiCNWs grown on substrate scratched with different sandpaper have different diameters. Therefore, SiC emitter properties can be tuned by controlling their diameter using different grade polishing sand paper.

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