本論文旨在製備碳化鎢(WCx)及氧化鎢(WOx)奈米線以作為場發射源及氣體感測器應用所需，在本文中所使用到的物性分析方法計有SEM、XPS、XRD和TEM等，電性分析方法則有真空下的電流-電壓量測。本論文分三部份，其中第一、第二部份分別介紹碳化鎢及氧化鎢奈米線的製備與分析結果，第三部份則包含傳統Fowler-Nordheim方程式與以數式近似來重建後的電流密度-電場曲線比較後的結果。
　　本論文第一部份實驗結果顯示，碳化鎢薄膜經退火處理進行碳化鎢(WCx)奈米線的製備，其最佳條件為退火溫度700C與退火時間30分鐘。製備所得之奈米線直徑與長度分別約為10-20 nm與100-280 nm。經由SEM觀察其表面形態並配合XPS、XRD和TEM進行材料及晶體結構分析顯示，所得奈米線之主要結晶結構為α-W2C。藉由場發射特性量測測得其起始電場約為1.7 V/m，與傳統奈米碳管相較之下，本研究之碳化鎢(WCx)奈米線具有極佳之場發射特性。本研究中亦針對膜厚、成長溫度、及時間等相關參數對所製備奈米線之影響進行探討分析。
　　本論文第二部份集中於氧化鎢(WOx)奈米線之製備，所採用方法有兩種，其一為利用前一部份在700C下所製備之碳化鎢(WCx)奈米線，在純氧的環境下進行第二階段的退火處理。實驗發現，原先之碳化鎢(WCx)奈米線於經歷氧化過程後消失，唯獨在400C、30分鐘退火後，發現尚有直徑及長度分別為7~15 nm與0.1μm奈米線存在，藉由TEM繞射分析，得知其為WOx的結晶結構，其中x介於2.7~2.9之間。方法二則使用濺鍍沈積後的碳化鎢薄膜，直接在不同的氮/氧比例下直接進行退火處理，變化溫度與時間參數以製備氧化鎢(WOx)奈米線。材料分析推估其主要成份為氧化鎢，成長溫度範圍介於500~75C之間，其場發射的起始電場約為4.8~6 V/m。實驗結果顯示，在不同溫度與時間之條件下製備氧化鎢奈米線之平均直徑及長度各不相同，而較低退火溫度所製備之奈米線其直徑相對較小。
　　本論文第三部份在於利用傳統Fowler-Nerdheim 方程式與modified Norde method摘取F-N參數之比較、以及藉由方程式 和數式近似的方法來重建場發射特性曲線。以在氮氣氣氛下，700C退火30分鐘和在氮氣環境中，以及600C退火1.5小時來重建場發射特性曲線。由重建後之曲線顯示單一的傳統F-N方程並不適合場發射特性曲線之重建，而 和數式近似之方法於重建特性曲線上較為合適，此項結果於場發射元件之模擬分析上將可提供極大助益。

　　In this thesis, the preparation of tungsten carbide (WCx) and tungsten oxide (WOx) nanowires are studied. SEM, XPS, XRD and TEM are employed for the characterization of WCx films and nanowires prepared in this study. Vacuum I-V measurement is employed to estimate the emission property of the prepared nanowires.
　　The self-synthesis of WCx nanowires by a simple thermal annealing WCx film in nitrogen is proposed in this work. In nitrogen ambient, the optimized annealing temperature and time for the self-synthesis of WCx nanowires are of 700C and 30 min, respectively. According to TEM measurements, the diameter and length of the nanowires are found to be about 10-20 nm and 100-180 nm, respectively. Material analysis indicates that the major crystallization of the nanowires consisting of α-W2C. Field emission measurements show that the turn-on electric field of the WCx nanowires prepared under optimum condition is about 1.7 V/m, which indicates that the WCx nanowires could be a potential candidate for field emission application as compared to CNTs. The influence of annealing time, temperature, and film thickness on the self-synthesis of nanowires are investigated.
　　An attempt to grow WOx nanowires using sputtered WCx films is also made by two different methods. The first method is the oxidization of self-synthesized WCx nanowires. It is found that nanowires disappeared after oxidation except the samples oxidized at 400C for 30 minutes. The obtained nanowires are with an average diameter and length of 7~15 nm and 0.1 m respectively. According to material analysis, it reveals that the major composition of the nanowires is WOx with x in the range of 2.7~2.9. The second method is thermal annealing of WCx film in O2/N2 ambient. Experimental results show that the self-synthesis of WOx nanowires could be achieved under thermal annealing at the temperature range of 500~750C for 30 min. The measured turn-on field of WOx nanowires was about 4.8~6 V/m. It is found that both the diameter and length of the WOx nanowires are dependent on the annealing temperature and time.
　　In the third part of this thesis, to properly describe the field emission characteristics of nanowires prepared in this work, conventional Fowler-Nordheim equation, F-N parameters by modified Norde method, equation, and mathematical fitting are examined and compared. Employing the measured data obtained from samples annealed at 700C for 30 minutes in nitrogen ambient and that annealed at 600　C for 1.5 hours in nitrogen, it is observed that the conventional F-N equation can not be well applied for experimental field emission characteristics of nanowires. On the contrary, equation and mathematical fitting are found to be much more favorable for the simulation of field emission device simulation.

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