【摘要】：氣敏傳感器作為檢測氣體的基礎(chǔ)器件,在工業(yè)生產(chǎn)和日常生活中均有著廣泛的應(yīng)用。在氣敏傳感器中,二氧化錫氣敏傳感器具有靈敏度高、響應(yīng)恢復(fù)特性好、成本低等優(yōu)點,是目前應(yīng)用最廣泛的一種氣敏傳感器。但隨著科技的進一步發(fā)展,對氣敏傳感器性能的要求越來越高,氣敏傳感器的敏感材料與結(jié)構(gòu)仍需要進一步的優(yōu)化。本文首先介紹了一種通過摻雜氯化鈀和石墨烯得到二氧化錫復(fù)合材料,獲得了一種能在近室溫下工作的乙醇氣體傳感器。二氧化錫粉末通過化學沉淀法得到,其表面疏松多孔的、由直徑約10-20 nm的納米顆粒組成。通過在該粉末中摻入不同配比的氯化鈀和石墨烯對比研究該復(fù)合材料對乙醇氣體的響應(yīng)特點。測試結(jié)果表明,摻入氯化鈀和石墨烯不僅可以降低傳感器的工作溫度,而且對靈敏度及響應(yīng)速度都有一定幅度的提升。特別是0.1 wt%rGO/3 wt%PdCl_2/SnO_2樣品,該樣品制備的傳感器可在40°C環(huán)境下工作,靈敏度為4.6,響應(yīng)時間為93 s,恢復(fù)時間為130 s,同時該傳感器具有良好的穩(wěn)定性與線性度。復(fù)合材料性能的提升主要是因為鈀離子對氧負離子吸附的促進作用以及石墨烯對低溫下載流子輸運能力的提高作用。本文之后設(shè)計了一種采用MEMS工藝制備的二氧化錫薄膜氣敏傳感器。通過有限元分析軟件分析了傳感器微加熱板模塊的熱效應(yīng),顯示結(jié)構(gòu)在80 mA加熱電流下可以提供375℃的溫度。之后采用相關(guān)工藝制備,其中二氧化錫薄膜通過磁控濺射法得到,經(jīng)SEM與AFM測試表明,該工藝制備的二氧化錫薄膜微觀上由納米顆粒組成,薄膜表面致密、高低起伏較小。經(jīng)過100ppm的乙醇氣體氣敏測試顯示,100 nm厚的二氧化錫薄膜氣敏傳感器的靈敏度在250℃時最高,達到3.1,但其電阻不能在該溫度下完全恢復(fù)。對比100nm、200nm、300nm厚的二氧化錫薄膜氣敏傳感器還發(fā)現(xiàn),隨著厚度的增加,傳感器的靈敏度減小。本文隨后提出采用異質(zhì)結(jié)修飾的方法,分別采用氧化鎳和氧化鎢對100 nm Sn02薄膜氣敏傳感器進行修飾。研究發(fā)現(xiàn),采用異質(zhì)結(jié)結(jié)構(gòu)能夠解決薄膜式氣敏傳感器電阻恢復(fù)的問題,且能使得傳感器靈敏度得到顯著提高。特別是5 nm NiO/100 nm SnO_2氣敏傳感器,其在250℃時的靈敏度可達7.9,相比于純二氧化錫薄膜提高了 155%,而且該傳感器對100 ppb的乙醇氣體仍具有一定響應(yīng),具有較好的低濃度響應(yīng)特性。
[Abstract]:As the basic device for gas detection, gas sensors are widely used in industrial production and daily life. Among the gas sensors, tin dioxide gas sensor is the most widely used gas sensor because of its high sensitivity, good response and recovery characteristics, low cost and so on. However, with the further development of science and technology, the performance of gas sensors is becoming more and more demanding, and the sensitive materials and structures of gas sensors still need to be further optimized. In this paper, we first introduce a kind of tin dioxide composite material obtained by doping palladium chloride and graphene, and obtain an ethanol gas sensor which can work at near room temperature. Tin dioxide powder was obtained by chemical precipitation method. The surface of tin dioxide powder is porous and composed of nanoparticles about 10-20 nm in diameter. The response of the composite to ethanol gas was studied by adding different proportions of palladium chloride and graphene into the powder. The results show that the addition of palladium chloride and graphene can not only reduce the working temperature of the sensor, but also improve the sensitivity and response speed of the sensor to a certain extent. Especially for the 0.1 wt%rGO/3 wt%PdCl_2/SnO_2 sample, the sensor can work at 40 擄C, the sensitivity is 4.6, the response time is 93 s, and the recovery time is 130s. At the same time, the sensor has good stability and linearity. The improvement of the properties of the composites is mainly due to the promotion of palladium ions on the adsorption of oxygen negative ions and the enhancement of the carrier transport capacity of graphene at low temperature. In this paper, a tin dioxide thin film gas sensor prepared by MEMS process is designed. The finite element analysis software is used to analyze the thermal effect of the sensor micro-heating plate module. It is shown that the structure can provide a temperature of 375 鈩，

本文編號：2335415