SnO2 thin film sensor with enhanced response for NO2 gas at lower temperatures

Abstract Semiconducting SnO2 thin films having higher value of electrical conductivity have been deposited using RF sputtering technique in the reactive gas environment (30% O2 + 70% Ar) using a metallic tin (Sn) target for detection of oxidizing NO2 gas. The effect of growth pressure (12–18 mTorr) on the surface morphology and structural property of SnO2 film was studied using Atomic force microscopy (AFM), Scanning electron microscopy (SEM) and X-ray Diffraction (XRD) respectively. Film deposited at 16 mTorr sputtering pressure was porous with rough microstructure and exhibits high sensor response (∼2.9 × 104) towards 50 ppm NO2 gas at a comparatively low operating temperature (∼100 °C). The sensor response was found to increase linearly from 1.31 × 102 to 2.9 × 104 while the response time decrease from 12.4 to 1.6 min with increase in the concentration of NO2 gas from 1 to 50 ppm. The reaction kinetics of target NO2 gas on the surface of SnO2 thin film at the Sn sites play important role in enhancing the response characteristics at lower operating temperature (∼100 °C). The results obtained in the present study are encouraging for realization of SnO2 thin film based sensor for efficient detection of NO2 gas with low power consumption.

[1]  Jun Zhang,et al.  NO2 sensing performance of SnO2 hollow-sphere sensor , 2009 .

[2]  T. Becker,et al.  Gas-kinetic interactions of nitrous oxides with SnO2 surfaces , 1998 .

[3]  John F. Vetelino,et al.  A semiconducting metal oxide sensor array for the detection of NOx and NH3 , 2001 .

[4]  José Pedro Santos,et al.  A thin film SnO2 gas sensor selective to ultra-low NO2 concentrations in air , 1997 .

[5]  K. Sreenivas,et al.  Contribution of adsorbed oxygen and interfacial space charge for enhanced response of SnO2 sensors having CuO catalyst for H2S gas , 2010 .

[6]  A. Dikovska,et al.  Investigation on the structural and optical properties of tin oxide films grown by pulsed laser deposition , 2005 .

[7]  Vinay Gupta,et al.  Improved response characteristics of SnO2 thin film loaded with nanoscale catalysts for LPG detection , 2008 .

[8]  M. C. Bhatnagar,et al.  Highly sensitive SnO2 thin film NO2 gas sensor operating at low temperature , 2007 .

[9]  T. Katsube,et al.  Highly sensitive NO2 gas sensor fabricated with RF induction plasma deposition method , 2004 .

[10]  Pietro Siciliano,et al.  Sprayed SnO2 thin films for NO2 sensors , 1999 .

[11]  Zhifu Liu,et al.  Influence of effective surface area on gas sensing properties of WO3 sputtered thin films , 2009 .

[12]  K. Sreenivas,et al.  Effect of annealing on refractive indices of radio-frequency magnetron sputtered waveguiding zinc oxide films on glass , 2004 .

[13]  Yasushi Yamada,et al.  Transient response of resistive-type NO2 sensor on temperature change , 2003 .

[14]  Young-Jin Choi,et al.  Novel fabrication of an SnO2 nanowire gas sensor with high sensitivity , 2008, Nanotechnology.

[15]  N. Bârsan,et al.  Parameter optimisation in SnO2 gas sensors for NO2 detection with low cross-sensitivity to CO: sol–gel preparation, film preparation, powder calcination, doping and grinding , 2000 .

[16]  K. Ihokura,et al.  The Stannic Oxide Gas SensorPrinciples and Applications , 1994 .

[17]  Rajesh Kumar,et al.  Effect of indium-doped SnO2 nanoparticles on NO2 gas sensing properties , 2007 .

[18]  G. Sberveglieri,et al.  Recent progress on gas sensors based on semiconducting thin films , 1998, 1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140).

[19]  Giorgio Sberveglieri,et al.  Tin oxide nanobelts electrical and sensing properties , 2005 .

[20]  S. Capone,et al.  Nanostructured In2O3-SnO2 sol-gel thin film as material for NO2 detection , 2006 .

[21]  K. Sreenivas,et al.  Fast response H2S gas sensing characteristics with ultra-thin CuO islands on sputtered SnO2 , 2003 .

[22]  Li Liu,et al.  Development of microstructure In/Pd-doped SnO2 sensor for low-level CO detection , 2009 .

[23]  Jérôme Brunet,et al.  An optimised gas sensor microsystem for accurate and real-time measurement of nitrogen dioxide at ppb level , 2008 .