Novel high sensitivity and selectivity semiconductor gas sensor based on the p+n combined structure

Abstract

In this paper, a new type semiconductor gas sensor of p+n combined structure is reported. The combined structure semiconductor gas sensor is a novel gas sensor that is based on the complementary feedback and complementary multiplication principle (Wu XH. United States Patent 5, 298, 783, 1994; Wu XH. Japan Patent 4-213212, 1992; Wu XH. China Patent 91108927, 1994; Wu XH, Li YF, Zhou ZL, Tian ZH. Chinese J Semicond 1993;14(7):439–44; Wu XH, Li YF, Zhou ZL, Tian ZH. Chinese J Semicond 1994;15(9):643–9; Wang YD, Wu XH. Proc Seventh Int Meeting Chem Sensors. Beijing, China, 1998). The sensor is composed of two sensitive bodies A and B whose conductive types are different. A is a p type material and B is an n type material. The results analyzed from a theoretical viewpoint showed that when A and B satisfied certain conditions, the sensor not only realized multiplication of sensitivity and selectivity, but also had better thermal stability. According to the sensor's structure and meeting conditions, we prepared the p+n type gas sensor for C 2H 5OH. The experimental results showed that they concurred with theoretical analysis very well.