Room-temperature-functioning ammonia sensor based on solid-state CuxS films

Resistive gas sensors based on copper sulphide (CuxS) are produced when a thick-film of the CuxS is chemically deposited on the polyethylene (PE) film substrates. The resistance response to gases is investigated for the sensors at the temperatures from 291 to 313 K in air. A correlation of the response to gas with the technology is analysed. It is demonstrated that the sensors are suitable for the detection of gases at the room temperatures. The response is detected to the traces of ethanol, acetone and some gases molecules of which include the (NHn)-group. The response and recovery times are equal to about a few tenths of seconds. The best results are obtained for the sensors when ammonia is used as the target gas. The response to ammonia is detected at the concentrations from 1 to 100 ppm of it in air. For a small amount of the target gas in air, the resistance is proved depending like power law on the gas concentration in air. (C) 2000 Elsevier Science S.A. All rights reserved.