Surface Activated ZnO Thick Film Resistors for LPG Gas Sensing

• Main Authors: D.R. Patil, L.A. Patil, G.H. Jain, M.S. Wagh, S.A. Patil
• Format: Article
• Language: English
• Published: IFSA Publishing, S.L. 2006-12-01
• Series: Sensors & Transducers
• Subjects: Zinc oxide; CuO-modified ZnO; LPG gas sensor; Gas response and recovery time
• Online Access: http://www.sensorsportal.com/HTML/DIGEST/december_06/P_106.PDF

The CuO-modified films obtained by dipping pure ZnO thick films into an aqueous solution of copper chloride for different intervals of time and fired at 500°C for 24 h. The copper chloride would transform into copper oxide upon firing. CuO-modified (0.4092 mass % CuO) ZnO thick films resulted in LPG gas detector. Upon exposure to 1000 ppm LPG gas, the barrier height between CuO-ZnO grains decreases markedly leading to a drastic decrease in resistance. An exceptional sensitivity was found to LPG gas at 400°C and no cross sensitivity was observed to other hazardous and polluting gases. The instant response (~ 5 sec) and fast recovery (~ 10 sec) are the main features of this sensor. The effects of microstructure and surfactant concentration on the gas response, selectivity, response time and recovery time of the sensor in the presence of LPG gas were studied and discussed.