Dimorphite based gas sensitive thin films

For the first time it was observed that thin films based on artificial dimo rphite (As4S3) exhibit gas sensitivity at room temperature. A sandwich meta l-semiconductor-metal (MSM) structure with dimorphite as the semiconducting material is used as chemical sensor for the detection of propylamine vapor . The gas induced shifts of the current-voltage characteristics as well as of the transient characteristics are studied. The interaction of propylamin e vapor with dimorphite leads to an increase of the current, which indicate s a gas induced doping effect. A dependence of the gas induced current on t he applied voltage and on the gas concentration is found. Results are discu ssed in terms of gas controlled trapping of injected carriers from electrod es which influences the space charge limited current. (C) 2000 Elsevier Sci ence S.A. All rights reserved.