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Nano Functional Ceramic Lab. 20120202 Outline •前言 •實驗步驟 •結果與討論 •結論 •未來工作 2 前言 · Recently, a variety of onedimensional (1D) nanostructures including nanowires, nanorods, nanobelts, nanosprings and nanorings have been produced. · These 1D nanostructures show very high surface-to-volume ratios and great surface activities, which could translate to better gas response and selectivity properties in terms of chemical sensing. · As an n-type semiconductor, SnO2 has been extensively exploited in applications related to gas sensing. · Recently, a hybrid structure of SnO2 nanorod thin films consisting of Q1D SnO2 nanorods embedded in a 2D SnO2 thin film matrix. The SnO2 nanorod thin film exhibited better sensing properties with faster response and shorter recovery time at lower operating temperatures. · In this paper, single SnO2 nanorod gas sensors have been fabricated by a focused ion beam (FIB). The sensing properties of the single SnO2 nanorod sensors towards H2 gas were studied. 3 實驗步驟 · 製備 SnO2 nanorod Precursor : (C4H9)2Sn(OOCCH3)2 二醋酸二丁基錫 Substrate : A 4 inch SiO2/Si wafer The wafer was inserted in a quartz boat perpendicularly. Oxygen was used as the reaction gas. The precursor vapor was carried into the deposition chamber by argon · No catalyst and additional substrate heating during deposition was performed. 4 實驗步驟 · 製備 SnO2 single-nanorod gas sensors 首先，把先前在SiO2/Si wafer 上生成的的SnO2 nanorod 刮下來 放進乙醇中，以超音波震盪分散 The Au/Ti electrodes (Au/Ti = 300/20 nm) were deposited on the SiO2/Si wafer by e-beam evaporation And were patterned by standard UV lithographic and liftoff processes. 利用微球管，把SnO2 nanorod suspension 滴在兩端電極中央，會形成 一個電場，以AC dielectrophoresis (5V, 1MHz) ， until the suspension completely dried out. liftoff processes: 剝離製程，為一 種常見的金屬圖 案成形法。 The SnO2 single-nanorod gas sensors were fabricated by connecting individual SnO2 nanorods to a pair of Au/Ti electrodes with Pt stripes deposited by focused ion beam. XRD SEM TEM I-V curve 實驗步驟 · Gas sensing 參考氣體: Air 帶測氣體: H2 , 100 ppm (dry air with total flow of 500 sccm) 溫度: 25 ℃ , 200 ℃ , 25 ℃~350 ℃ Response: R air R H2