【正文】 Semiconductor gas sensors detect gases from a change in electrical resistance of an element made with a semiconductive metal oxide, typically SnO2. Although sensors utilizing γFe2O3 or αFe2O3 have been put into practical use, SnO2 sensor still has an overwhelming market share. The production of semiconductor gas sensors has grown into a large industry: more than 5 million pieces were produced in 1983. Most of them have been used in domestic homes as detectors or alarms for gas leakage. Field statistics has shown that gas alarms are quite effective to prevent an outbreak of gas leakage accident。 the accident rate sharply decreases with an increase in gas alarm installation rate. It is useful to know actual Ltd. has analyzed the cases where gas alarms were effective for prevention of disastorous gas accidents. The result is shown in . The causes are associated dominantly with mishanding or defects of gas appliances (%), and then with stopcocks (%), suicides (%), gas pipes (%), connectors (%), and the others (%). It is rather surprising that suicides are ranked in the third place in this analysis. Anyway semiconductor gas sensors have been so far given much credit as an important device for home security and the installation rate of gas alarms is increasing year after year. Several years ago a problem arose about SnO2 gas sensor when it was adopted at places like kitchens of underground restaurants where various inflammable gases came out into atmosphere from fuels and cookings very frequently during working time. In such a dirty atmosphere, the gas sensor tended to given an alarm at an inflammable gas concentration which was lowered gradually with an elapse of operation time. It has been pointed out that the problem was contributed by various factors but was associated most profoundly with the lowering of electric resistance of the sensor element due to its sintering at unexpectedly high working temperatures. The problem have been almost solved after revisions were made to the sensor element. Semiconductor gas sensors is being applied in various fields, domestic and industrial. Carbon monoxide has often been used as a sample gas for gas sensor researches. However, reliable CO sensors using SnO2 were . Breakdown of causes of gas leakage . Heater voltage and output(according to Osaka Gas Company Ltd.) voltage time for a SnO2 based CO sensordeveloped only recently. The sensitivity of SnO2 sensor to CO is low at elevated temperatures below 100oC. On the other hand, operation at such low temperature is easily disturbed by contamination of the sensor surface with interfering gases such as water vapor and others. Thus the recently developed CO sensor adopts intermittent heat cycles during operation。 sensor is heated to elevated temperature (300400oC) to make the sensor surface clean while CO detection is made at a low temperature as shown in . Combustion monitor sensors have been also developed by using SnO2 and perovskitetype oxide (La1xSrxCo1yFeyO3), respectively. These sensors measure the stoichiometric ratio of air to fuel, and applicable to kerosene or gas stoves, hot water supply systems, and so on. The sensor elements so far used practically are all porously sintered blocks of semiconductive oxides. However, thick film elements, which seem to be more patible with large scale production and sensor integration, have been nearly developed for mercial production.譯文： 半導(dǎo)體氣敏傳感器在過去的十年間，氣敏傳感器的研究和發(fā)展已經(jīng)有了很大的的進(jìn)步。除了其它方面的應(yīng)用， 以SnO2為主的半導(dǎo)體傳感器作為液化氣和民用煤氣泄漏的檢測器和報警器來使用，已經(jīng)越來越盛行。 1975年被提議的基于 MOSFET 的氣敏傳感器, 引起了許多研究員的興趣，并發(fā)展成為商品化的氫檢測器。 由穩(wěn)定的氧化鋯組成的固體電解質(zhì)已證明是對氧氣，SO2等的非常有前景的傳感材料。被穩(wěn)定的氧化鋯表現(xiàn)的固體電解物,已經(jīng)證明是氧， SO2 等的非常有希望的感應(yīng)器材料。本文著眼于簡要回顧近年來半導(dǎo)體氣敏傳感器的進(jìn)步和發(fā)展趨勢。 半導(dǎo)體氣敏傳感器通過半導(dǎo)體的金屬氧化物電阻值的改變來檢測氣體，典型的氧化物如SnO2。 盡管利用γ Fe2O3 或α Fe2O3 制成的傳感器已經(jīng)付諸實踐，SnO2 感應(yīng)器仍然有一個壓倒性的市場占有率。 半導(dǎo)體氣敏傳感器的生產(chǎn)已經(jīng)發(fā)展成了一個很大的產(chǎn)業(yè)，1983年就生產(chǎn)了超過500萬片。它們大多數(shù)被用來作為家庭煤氣泄漏的檢測和報警器。 業(yè)內(nèi)統(tǒng)計顯示氣體報警器對于防止氣體泄漏事故的發(fā)生非常有效；隨著報警器安裝率的提高，事故發(fā)生率有了顯著的下降。 知道氣體報警減少意外事故的發(fā)生的起因是非常有用的。圖1給出了結(jié)果。其中，%，%，%，%，%，%。很相當(dāng)令人驚訝地的是, 自殺在這項分析中排到了第三位。 不管怎么說半導(dǎo)體氣敏傳感器作為家庭安全的重要設(shè)施到目前為止已經(jīng)建立了很好的信譽(yù)，它的安裝率正在逐年上升。幾年前，SnO2用在像地下餐館的廚房這樣的地方，那里許多可燃性氣體不斷地從燃料中進(jìn)入到空氣中，這樣問題就隨之而來了。在這樣骯臟的大氣中，傳感器容易隨時間推移漸漸降低性能。人們指出問題的形成有許多因素，主要是因為它在出乎意料的高溫下燒結(jié)的低電阻值形成的。這個問題在對材料元素作了改進(jìn)后已經(jīng)得到了解決。 半導(dǎo)體氣敏傳感器正被應(yīng)用到許多領(lǐng)域，家庭和工業(yè)。 一氧化碳時常被用當(dāng)做一種樣品瓦斯作為感應(yīng)器研究。 然而，使用 SnO2 的可靠 CO 傳感器最近才有發(fā)展。 在100C以下 SnO2 傳感器對CO的靈敏性很低。另一方面，在如此低的溫度操作容易被水蒸氣等其它氣體干擾。 于是，最近研制的CO傳感器在操作中采用了間歇循環(huán)加熱；傳感器被加熱300400C以使在低溫檢測CO時，傳感器表面能不受干擾，具體如圖2所示。 燃燒監(jiān)視器感應(yīng)器也由 SnO2 和 鈣鈦礦 類型氧化物 (La1xSrxCo1yFeyO3)制成。 這些傳感器可測量空氣的燃?xì)獗嚷?，?yīng)用到煤氣爐，熱水供應(yīng)系統(tǒng)等方面。到目前為止，這些傳感器都是用半導(dǎo)體氧化物燒結(jié)而成。 然而，厚膜元素看起來更適合于較大測量范圍的傳感器，并且已經(jīng)發(fā)展成為了商業(yè)化的產(chǎn)品。附錄2： 參考文獻(xiàn)1. 《單片機(jī)接口技術(shù)及在工業(yè)控制中的應(yīng)用》 陜西電子編輯部 李秉操,張登舉,付壽英,徐飛 編著2. 《單片機(jī)微型機(jī)算計實用系統(tǒng)設(shè)計》 人民郵電出版社 潘新民,王燕芳 編著3. 《模擬電子技術(shù)基礎(chǔ)》 西安電子科技大學(xué)出版社孫肖子 張企民 編著4. 《新編單片機(jī)原理與