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| 題 名 | 氧化鈀奈米片薄膜對一氧化碳氣體感測特性研究=CO Gas Sensing by PdO Nanoflake Thin Film |
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| 作 者 | 施博翔; 江昱儒; 林心弘; 潘扶民; | 書刊名 | 真空科技 |
| 卷 期 | 24:4 2011.12[民100.12] |
| 頁 次 | 頁30-36 |
| 分類號 | 448.552 |
| 關鍵詞 | 氧化鈀; 奈米片; 一氧化碳; 氣體感測; 活性濺鍍沉積法; PdO; Nanoflake; CO; Gas sensor; Reactive sputter deposition; |
| 語 文 | 中文(Chinese) |
| 中文摘要 | 本研究以活性濺鍍法沉積氧化鈀 (PdO) 奈米片薄膜，探討 PdO 對一氧化碳 (CO) 氣體感測的電性響應。PdO 奈米片厚度僅十數奈米，表面因氣體吸附伴隨之電荷轉移會在薄片形成大範圍之空間電荷區，使薄膜電性發生顯著變化，同時該薄膜具有巨大表面積可吸附大量CO 分子，提昇感測靈敏度。研究發現，PdO 薄膜在 200oC 時，對 CO 感測有最佳的響應速率與靈敏度，薄膜吸附 CO 分子後，電阻值升高，顯示奈米片內產生電荷空乏區，而 PdO 為 p型半導體，此現象似乎為吸附之 CO 傳輸負電荷至薄膜，降低主載子電洞密度。XPS 分析顯示在 200oC 感測環境下，PdO 表面被還原成金屬 Pd，因感測於真空中進行，缺乏氧氣氧化被還原之金屬 Pd，因此薄膜對 CO 感測的靈敏度為 CO 吸附在 PdO 或 Pd 金屬表面仍有待於大氣中感測來釐清。 |
| 英文摘要 | This study deposited PdO nanoflake thin films on the SiO2/Si substrates by reactive sputter deposition, and investigated CO sensing properties of the PdO thin fi lm. The nanofl ake has a single crystalline structure after thermal anneal at temperatures >200oC. As CO adsorption occurs on the nanofl ake, the space charge region, which results from charge transfer between CO adsorbates and the PdO thin fi lm, will occupy most volume of the ultrathin nanofl ake, thereby dramatically changing electrical properties of the thin fi lm. Moreover, the nanofl ake thin fi lm can adsorb a large amount of CO molecules as a result of the large surface area and, therefore, the PdO nanofl ake thin fi lm should have a high sensitivity toward CO gas sensing. According to our study, the PdO thin fi lm has the best CO sensing performance at 200oC, including a fast response time (<10 sec), a high sensitivity and a good reproducibility. Because PdO is a p-type semiconductor, the electrical resistivity of the PdO thin fi lm increases upon CO adsorption, indicating that the depletion region is formed in the nanoflake. This observation suggests that negative charges transfer from the CO adsorbate to the PdO nanoflake, inducing the reduction in the majority carrier density. X-ray photoelectron spectroscopy analysis shows that the PdO surface is reduced to metallic Pd at 200oC. Because our experiments were carried out under a vacuum condition of 1x10-2 torr, re-oxidation of metallic Pd during experiment was unlikely. To clarify whether the change in the electrical property of the PdO thin fi lm is a result of CO adsorption on the PdO or the Pd surface, we have been undertaking the CO sensing experiment under the dry air condition. |
本系統中英文摘要資訊取自各篇刊載內容。