本研究利用三區爐管，以金屬鎵為前驅物，真空幫浦將爐管腔室抽氣至約0.02 Torr的低壓環境，透過化學氣相沉積方式及固-液-氣機制加熱合成β-氧化鎵奈米線。為了提升β-氧化鎵奈米線之光催化以及氣體感測性能，本研究以奈米銀粒子修飾，減少電子電洞對複合與增加接觸待測氣體的面積。首先透過SEM確認奈米線形貌，後以XRD與TEM確定奈米線結構，並透過EDS與XPS確認元素組成與化學鍵結情況。電性方面，使用四點探針方法得出單根β-氧化鎵奈米線的電阻率為7.62*10-1 Ω‧cm。氣體感測實驗，本研究以5ppm之CO與20ppm之乙醇作為感測氣體，在100度至200度之間進行響應值量測，發現修飾濃度與溫度越高，CO與乙醇的響應越好，在200℃時，5%銀修飾之奈米線的響應分別可以達到16.3與36.1，證明修飾銀奈米粒子可以增加奈米線與待測氣體面積和生成較大的電子空乏層以增加響應。光催化實驗以10ppm之亞甲基藍作為主要降解液，發現2%銀修飾的氧化鎵奈米線在140分鐘的光照下之催化效果為74%，較純氧化鎵的57%與5%銀修飾的62%更好，證明修飾ㄧ定濃度的貴重金屬粒子可以有效提升氧化鎵奈米線的光催化降解效果，然而濃度若過大，材料表面與降解液的反應面積會減少，銀粒子在奈米線基板上團簇而導致光催化效果不增反減。

In this study, high density and crystallinity β-gallium oxide nanowires were successfully synthesized via CVD through vapor-liquid-solid mechanism. Silver nanoparticles were modified on the surface of β-gallium oxide nanowires with high crystallinity. The results of response to CO and ethanol gas indicate that 5% Ag@β-Ga2O3 had best response to CO and ethanol gas with 16.3 and 36.1 at 200℃, respectively. The modification effectively enhanced the response to gas as a result of increased active reaction spots and generated Schottky barrier.
For photoactivities of nanowires, 2% Ag@β-Ga2O3 degraded 74% of MB solution and the reaction rate constant was 0.00952 after 140 minutes of irradiation, better than the performances of β-Ga2O3 and 5% Ag@β-Ga2O3. In theory, the functionalization of silver nanoparticles can increase reaction area and decrease the charge recombination rate. However, the excess amount of decoration may shield nanowires from absorbing photons. To sum up, a proper amount of silver nanoparticles decoration can significantly enhance the photocatalytic and gas sensing properties of β- Ga2O3.

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