Unusual electrical response of a poly(aniline) composite film on exposure to a basic atmosphere and its application to sensors

Abstract

An unusual electrical response of a poly(aniline) composite film on exposure to a basic atmosphere is reported in this paper. Based on this feature, it was possible to develop a novel kind of gas-sensor exhibiting high sensitivity, rapid response, good repeatability which can be easily recovered by purging with highly pure N₂. In order to study the gas-response mechanism of this unusual electrical response, comparative tests were carried out on the gas-sensing properties of N-type and P-type silicon with porosity under similar conditions. The electric field-induced surface photovoltage spectrum (FISPS) on the poly(aniline) composite film before and after pretreatment was also examined. The experimental results indicated that the transition from P-type to N-type of a poly(aniline) composite film may exist as a result of a doping effect.