Effect of dispersal of Pd nanocatalysts on H2 sensing response of SnO2 thin film based gas sensor Manish Kumar Verma, Neha Batra, Monika Tomar, Vinay Gupta Materials Research Society Symposium Proceedings, 2013 SnO2 based sensor structures prepared by rf magnetron sputtering technique have been studied for detecting H2 gas. Pd catalyst was integrated onto the SnO2 thin film in the form of clusters and nano-particles to obtain enhanced sensing response characteristics. The prepared sensor structures have been studied over a temperature range of 50-250°C for sensing response towards 500 ppm H2 gas. The sensor with Pd catalyst dispersed in the form of nanoparticles was found to exhibit an enhanced sensing response of 1.9×103 at a relatively low operating temperature of 150°C with a fast response time of 2 s and recovery time of 65 s towards 500 ppm H2 gas. The origin of enhanced sensing response is identified in the light of the enhanced spill over of H2 gas molecules on the uncovered surface of SnO2 thin film.
SnO2-CuO nanocomposite thin film sensor for fast detection of H2S gas Manish Kumar Verma, Vinay Gupta Journal of Experimental Nanoscience, 2013 SnO2 thin film and SnO2–CuO nanocomposite thin film sensors have been realised by pulsed laser deposition (PLD). The prepared sensor structures have been studied for the sensing response characteristics in the presence of 20 ppm H2S gas. An enhancement in the response was observed from 1.4 × 102 for bare SnO2 thin film sensor to 4.3 × 103 for SnO2–CuO composite sensor with a fast response (t 90) time of about 2 s. The enhanced response has been attributed to the highly porous morphology of the films grown by PLD besides the modulation of space charge region due to spillover of H2S gas molecules on the surface of SnO2 film by the CuO catalyst.
Enhanced response of pd nanoparticle-loaded SnO 2 thin film sensor for H 2gas Manish Kumar Verma, Vinay Gupta IEEE Sensors Journal, 2012 The sensing response of <formula formulatype="inline"><tex Notation="TeX">${\\rm SnO}_{2}$</tex></formula> thin film sensors loaded with Pd nanoparticles <formula formulatype="inline"><tex Notation="TeX">$({\\rm Pd}\\hbox{-}{\\rm SnO}_{2})$</tex></formula> is studied for <formula formulatype="inline"><tex Notation="TeX">${\\rm H}_{2}$</tex></formula> gas. Nanoparticles of Pd catalyst of varying size (2–6 nm) are synthesized using chemical route with different concentrations of polyvinyl pyrollidone (PVP) as a stabilizing agent and dispersed over the surface of <formula formulatype="inline"><tex Notation="TeX">${\\rm SnO}_{2}$</tex></formula> thin film deposited by rf magnetron sputtering technique. The sensing response of all prepared sensors was recorded over a temperature range of 50<formula formulatype="inline"><tex Notation="TeX">$^{\\circ}{\\rm C}$</tex></formula>–200<formula formulatype="inline"> <tex Notation="TeX">$^{\\circ}{\\rm C}$</tex></formula>. The effect of PVP used for synthesis of Pd nanoparticles has been studied on the sensing response characteristics of <formula formulatype="inline"><tex Notation="TeX">${\\rm Pd}\\hbox{-}{\\rm SnO}_{2}$</tex></formula> sensors. The optimized sensor structure was found to exhibit a higher response <formula formulatype="inline"> <tex Notation="TeX">$(1.9\\times 10^{3})$</tex></formula> at a relatively low operating temperature (150<formula formulatype="inline"> <tex Notation="TeX">$^{\\circ}{\\rm C}$</tex></formula>) with fast response time <formula formulatype="inline"><tex Notation="TeX">$({\\rm t}_{90}\\sim 2~{\\rm s})$</tex></formula> for 500 ppm <formula formulatype="inline"><tex Notation="TeX">${\\rm H}_{2}$</tex></formula> gas. The origin of enhanced sensing response is identified in the light of the interaction of PVP with Pd nanoparticles besides the spill over of <formula formulatype="inline"><tex Notation="TeX">${\\rm H}_{2}$</tex></formula> gas molecules on the uncovered surface of <formula formulatype="inline"><tex Notation="TeX">${\\rm SnO}_{2}$</tex></formula> thin film.
Bi-layered sensor structures (SnO2 film-CuO nanolayer) with improved response characteristics for H2S gas Manish Verma, K Sreenivas, Vinay Gupta, Arijit Chowdhuri Proceedings of IEEE Sensors, 2009 Two sensor structures (SnO<inf>2</inf> film, and SnO<inf>2</inf> film-CuO nanolayer) have been prepared in the present study using both rf sputtering and pulsed laser deposition (PLD) techniques for trace level detection of H<inf>2</inf>S gas (20 ppm). The response characteristic of sensor structures based on bare SnO<inf>2</inf> thin film (90 nm) and after integrating with catalytic CuO nanolayer (10 nm) have been investigated and a comparative study has been carried out in detail. The bilayer sensor structures (SnO<inf>2</inf> film-CuO nanolayer) prepared by both techniques exhibits enhanced sensitivity in comparison to bare SnO<inf>2</inf> film sensor. PLD grown SnO<inf>2</inf>-CuO bilayer structure shows maximum sensor response (∼2.3×10<sup>3</sup>) at a very low operating temperature of 100°C.
