title: Effect of air-pressure on room temperature hydrogen sensing characteristics of nanocrystalline doped tin oxide MEMS-based sensor.
abstract: Nanocrystalline indium oxide (In2O3)-doped tin oxide (SnO2) thin film sensor has been sol-gel dip-coated on a microelectrochemical system (MEMS) device using a sol-gel dip-coating technique. Hydrogen (H2) at ppm-level has been successfully detected at room temperature using the present MEMS-based sensor. The room temperature H2 sensing characteristics (sensitivity, response and recovery time, and recovery rate) of the present MEMS-based sensor has been investigated as a function of air-pressure (50-600 Torr) with and without the ultraviolet (UV) radiation exposure. It has been demonstrated that, the concentration of the surface-adsorbed oxygen-ions (which is related to the sensor-resistance in air), the ppm-level H2, and the oxygen (O2) partial pressure are the three major factors, which determine the variation in the room temperature H2 sensing characteristics of the present MEMS-based sensor as a function of air-pressure.
authors.affiliation: Surface Engineering and Nano Fabrication Lab, Advanced Materials Processing and Analysis Center and Mechanical Materials, Aerospace Engineering Department, University of Central Florida, USA.
authors.forename: Satyajit
authors.initials: S
authors.lastname: Shukla
authors.forename: Lawrence
authors.initials: L
authors.lastname: Ludwig
authors.forename: Hyoung J
authors.initials: HJ
authors.lastname: Cho
authors.forename: Julian
authors.initials: J
authors.lastname: Duarte
authors.forename: Sudipta
authors.initials: S
authors.lastname: Seal
mesh_terms: D000388:Air; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D004867:Equipment Design; D006859:Hydrogen / Q000737:chemistry; D007204:Indium / Q000737:chemistry; D007477:Ions; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D010100:Oxygen / Q000737:chemistry; D010313:Partial Pressure; D011312:Pressure; D012680:Sensitivity and Specificity; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D017971:Tin Compounds / Q000737:chemistry*; D014159:Transducers; D014466:Ultraviolet Rays
chemical_list: D007477:Ions; D017971:Tin Compounds; D007204:Indium; C047711:indium oxide; D006859:Hydrogen; C045358:stannic oxide; D010100:Oxygen