本文關(guān)鍵詞： ZnO 納米棒 分等級結(jié)構(gòu) ZnO/SnO2 ZnO/ZnFe2O4 氣體傳感器　出處：《吉林大學》2015年碩士論文　論文類型：學位論文

【摘要】：在諸多的納米材料中，，ZnO作為一種直接帶隙寬禁帶半導體材料，具有優(yōu)異的電、光和磁等性能，被廣泛地應(yīng)用于各個領(lǐng)域，尤其是在光電器件和氣體傳感器領(lǐng)域。大量研究證明，器件的性能與材料的結(jié)構(gòu)與微觀形貌密切相關(guān)。所以，不同尺寸和形貌的ZnO納米結(jié)構(gòu)已經(jīng)通過各種物理化學方法制備而成。一維（1D）的ZnO納米結(jié)構(gòu)具有高的比表面積、大的活性位點密度以及優(yōu)異的物理化學特性，被認為是制作微觀納米級光電器件和氣體傳感器的優(yōu)質(zhì)材料。另一方面，由低維的ZnO納米材料和其他氧化物組裝而成的分層、多孔及空心結(jié)構(gòu)的復合氧化物作為氣體傳感器的敏感層可以顯著提高氣敏性能。為了制備大面積的分等級結(jié)構(gòu)納米薄膜，本論文采用簡單的超聲噴霧熱分解法，在玻璃襯底上原位合成出一維ZnO納米棒，并以此為模板二次生長制備出分等級結(jié)構(gòu)ZnO/SnO2、ZnO/ZnFe2O4納米薄膜。具體研究內(nèi)容如下： 1）采用簡單的超聲噴霧熱分解法制備出一維ZnO納米棒陣列，ZnO納米棒的長度約為9μm。通過改變反應(yīng)時間控制納米棒的長度，由此獲得了樣品的形態(tài)演化趨勢，進而給出了一種可能的ZnO納米棒生長機制。另外，我們還測試了在室溫下的光致發(fā)光譜，測試結(jié)果表明所制備的ZnO納米棒陣列光致發(fā)光譜是由一個強紫外發(fā)射峰和一個寬的綠光發(fā)射峰組成。 2）通過兩步超聲噴霧熱分解法制備了中空圓梳狀ZnO/SnO2復合敏感材料，并構(gòu)建了高性能乙醇氣體傳感器。ZnO/SnO2分等級納米結(jié)構(gòu)是由ZnO納米棒和二次生長的納米線組成。在納米線生長過程中，ZnO納米棒的內(nèi)部變成中空結(jié)構(gòu)。通過TEM表征發(fā)現(xiàn)，二次生長的納米線是由ZnO和SnO2兩種材料共同組成的。由內(nèi)而外的奧斯特瓦爾德熟化機理可以解釋這種空心納米結(jié)構(gòu)的形成。氣敏特性結(jié)果顯示，以所制備的ZnO/SnO2為敏感材料的傳感器在275℃對100ppm的乙醇響應(yīng)值達到10。 3）為了提升ZnO納米棒陣列的氣敏特性，我們通過簡單的兩步合成法構(gòu)筑了分等級結(jié)ZnO/ZnFe2O4納米森林，將制備的ZnO納米棒浸漬在0.2M的FeSO4溶液中再經(jīng)過烘干燒結(jié)后得到。氣敏測試結(jié)果表明，與單一ZnO納米棒陣列相比，分等級結(jié)構(gòu)ZnO/ZnFe2O4對乙醇有更高的靈敏度和更快速的響應(yīng)。 綜上所述，本論文采用超聲噴霧熱分解法在石英襯底上制備出一維有序的ZnO納米棒陣列。為了進一步提升ZnO納米棒的氣體傳感特性，我們采用半導體復合技術(shù)對敏感材料進行了改性，制備出分等級結(jié)構(gòu)ZnO/SnO2和ZnO/ZnFe2O4復合氧化物。復合后的材料對100ppm乙醇的靈敏度與單一材料相比，其靈敏度得到明顯提升。異質(zhì)結(jié)的勢壘高度在不同氣氛中的變化可能是復合氧化物傳感性能提升的主要原因。
[Abstract]:As a direct bandgap wide bandgap semiconductor material, ZnO has been widely used in many fields, especially in the field of optoelectronic devices and gas sensors, due to its excellent electrical, optical and magnetic properties. The properties of the devices are closely related to the microstructure and morphology of the materials. Therefore, the ZnO nanostructures with different sizes and morphologies have been prepared by various physical and chemical methods. Large active site density and excellent physical and chemical properties are considered to be excellent materials for fabricating micro nanometer optoelectronic devices and gas sensors. On the other hand, lamination made of low dimensional ZnO nanomaterials and other oxides, The composite oxides with porous and hollow structures can improve the gas sensing performance significantly. In order to prepare large area graded nanofilms, a simple ultrasonic spray pyrolysis method is used in this paper. One-dimensional ZnO nanorods were synthesized on glass substrates in situ and used as templates to prepare graded ZnO / Sno _ 2 / ZnO / ZnFe _ 2O _ 4 nanocrystalline films. 1) the length of one-dimensional ZnO nanorods prepared by simple ultrasonic spray pyrolysis method is about 9 渭 m. By changing the reaction time to control the length of nanorods, the morphologic evolution trend of the samples is obtained. Furthermore, a possible growth mechanism of ZnO nanorods is given. In addition, we have also measured the photoluminescence spectra at room temperature. The results show that the photoluminescence spectra of the ZnO nanorods array are composed of a strong ultraviolet emission peak and a wide green emission peak. 2) Hollow circular comb ZnO/SnO2 composite sensitive materials were prepared by two-step ultrasonic spray pyrolysis. The high performance ethanol gas sensor. ZnO / Sno 2 nanostructure is composed of ZnO nanorods and secondary growth nanowires. During the growth of nanowires, the inner structure of ZnO nanorods becomes hollow. It is found by TEM characterization. The secondary growth nanowires are composed of two kinds of materials, ZnO and SnO2. The formation of this hollow nanostructure can be explained by Ostwald aging mechanism from inside to outside. The sensor with ZnO/SnO2 as the sensitive material has a response value of 10. 5% to 100 ppm ethanol at 275 鈩

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