本研究利用雙靶反應式射頻共濺鍍法製備摻雜鐵之氧化鎢薄膜於玻璃基板上，並改變不同沉積條件，探討薄膜成分、結構及價態，對氣體感測性質之影響。薄膜結構以XRD、SEM、EDS、XPS等各項分析儀器進行分析，並利用本實驗室組裝之氣體感測儀器，分別針對一氧化碳、二氧化碳、甲醇、乙醇及丙酮五種目標氣體做氣體感測分析。
根據實驗結果，與純氧化鎢薄膜相比，摻雜鐵確實能有效提升對於氣體之響應，且於650˚C下沉積摻雜鐵之氧化鎢薄膜在固定工作溫度350˚C下，對5ppm丙酮有最佳的敏感度。由SEM表面形貌觀察可發現鐵的摻雜可抑制晶粒成長，使其無法成長為緻密之薄膜，晶粒間產生孔洞，可增加提供氣體吸附的位置，有利於氣體感測分析。實驗結果亦發現隨著沉積時間的拉長，氣體感測響應值有顯著提升，經由XPS分析顯示是因結構中混有較多比例的低價態鎢之緣故。針對實際運用之需要，本研究也進行氣體感測響應值之再現性實驗，針對5 ppm之丙酮氣體反覆測試100次，實驗結果顯示對丙酮氣體之響應沒有明顯的衰退，其響應值僅由35.8稍降為32.3，顯示薄膜具有相當的穩定性及再現性。

In this research, Fe-doped tungsten oxide films were deposited on glass substrates by RF magnetron sputtering to analyze their gas sensing capabilities. The films were grown at substrate temperatures from 400 °C to 650 °C and under different deposition conditions. The gas sensing performance of the films was measured at a working temperature of 350 °C for five target gases (CO, CO2, methanol, ethanol, and acetone) at the concentration of 5 ppm. The gas sensitivity (S) was defined as S=Rair/Rgas, where Rgas and Rair represent the resistances measured in target gas and in air, respectively. The results showed that the Fe-doping in tungsten oxide films enhanced gas sensitivity as compared to the undoped films. In particular, the Fe-doped films deposited at 650 °C for 45 minutes had the best sensitivity of S=35.8 to 5 ppm acetone. The experiment also found that as the deposition time increased, the acetone sensitivity of the grown films increased significantly. XPS analysis showed an increased level of low-valence tungsten in such films, which might be the reason for the increased acetone sensitivity. The microstructure of Fe-doped WO3-x films consisted of porous surfaces and fibrous cross-section, which were beneficial to gas sensing applications, because such a microstructure provided an excellent condition for gases to diffuse into the films. To determine the practical applicability of the films, repeatability tests were also conducted. The 5 ppm acetone gas and air were alternately injected into the measurement chamber for 100 times, and the results indicate that the sensitivity remained above 32 after the 100 runs, without a notable decrease from the initial value of 35.8. The results indicated that Fe-doped WO3-x films had good stability and repeatability for gas sensing application.

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