Gas Sensing Performance of Undoped(Pure)and Doped ZnO Thick Films

Presently the atmospheric pollution has become a global issue. Toxic and inflammable gases cause serious atmospheric pollution. These gases exist in both domestic and industrial environments. In order to detect measure and control these gases one should know the amount and type of gases present in the ambient. Thus the need to monitor and control these gases has led to the research and development of wide variety of sensors using different materials and technologies. For over fifty year’s semiconductors specifically metal oxide-based semiconductors have been studied in gas sensing applications. Metal oxide semiconductor (MOS) materials such as SnO2 ZnO TiO2 WO3 etc. are considered to be better materials for chemical sensors as compared to other gas sensing materials. Now a day there is a general opinion in both scientific and engineering community that there is an urgent need for the development of cheap reliable sensors for the control detection and measuring systems. The research has been focused on n-type semiconducting oxides ZnO is one of the MOS sensitive to many sorts of gases at moderate temperature hence it is one of the most widely applied oxide-gas sensor.