Title :
Study of SnO2 and SnO2:CuO thin films for H2S gas sensing applications
Author :
Kaur, Manmeet ; Betty, C.A. ; Muthe, K.P. ; Vyas, J.C. ; Katti, V.R. ; Gupta, S.K. ; Gadkari, S.C. ; Yakhmi, J.V.
Author_Institution :
Tech. Phys. & Prototype Eng. Div., Bhabha Atomic Res. Centre, Mumbai, India
Abstract :
SnO2:CuO thin films have been identified earlier as highly sensitive and selective H2S gas sensors. Usually the sensors are characterized by measuring dc resistance. In the present study ac impedance spectroscopy has been used to investigate the effect of cupric oxide addition on H2S sensing properties of polycrystalline SnO2 based thin film sensors. For this two types of thin films-pure SnO2 and SnO2:(0.5 wt%)CuO, were studied. It has been observed that the total impedance of the films has two contributions: one due to grains (intragranular) and other from grain boundaries (intergranular). On exposure to H2S gas, it was seen that for SnO2 films, the intergranular resistance drops by a factor of 6 while for SnO2:CuO films this reduction is by a factor of 107. These results support earlier studies, that high sensitivity in SnO2:CuO films is due to destruction of p-n junctions formed at grain boundaries.
Keywords :
copper compounds; electrochemical impedance spectroscopy; gas sensors; grain boundaries; hydrogen compounds; semiconductor thin films; tin compounds; H2S; H2S gas sensors; SnO2 thin films; SnO2:CuO; SnO2:CuO thin films; ac impedance spectroscopy; grain boundaries; intergranular resistance; p-n junctions; polycrystalline SnO2 based thin film sensors; Electric resistance; Electrical resistance measurement; Equivalent circuits; Gas detectors; Heating; Impedance measurement; Temperature measurement; Temperature sensors; Thin film sensors; Transistors;
Conference_Titel :
Intelligent Sensing and Information Processing, 2004. Proceedings of International Conference on
Print_ISBN :
0-7803-8243-9
DOI :
10.1109/ICISIP.2004.1287658
