Preparation, Property, and Mechanism Studies of Amorphous Ferroelectric (Ba, Sr)TiO3 Thin Films for Novel Metal–ferroelectric–metal Type Hydrogen Gas Sensors

2000 ◽  
Vol 15 (6) ◽  
pp. 1291-1302 ◽  
Author(s):  
W. Zhu ◽  
O. K. Tan ◽  
J. Deng ◽  
J. T. Oh
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Gas Sensing ◽  
Sol Gel ◽  
Interfacial Polarization ◽  
Polarization Potential ◽  
Hydrogen Gas ◽  
Ferroelectric Thin Films ◽  
Interesting Phenomenon ◽  
High Dielectric

Ferroelectric(Ba0.67Sr0.33)TixO3 (BST) thin films with x = 0.98, 1.00, 1.02, and 1.04 were prepared by the sol-gel technology, and their thermal, structural, dielectric, and gas sensing properties were systematically characterized. The amorphous (Ba0.67Sr0.33)TixO3 thin film capacitive devices were made on Si substrate to detect hydrogen gas and to study hydrogen-induced interfacial polarization potential.Experimental results showed that the Schottky I–V behavior appears in these Pd/amorphous BST thin film/metal capacitive devices and that enhanced interfacial dipole potentials as large as 4.5 V at 1000 ppm hydrogen gas in air were newly observed, which is about 7 times larger than the best value reported under similar testing conditions. It was clearly shown that the hydrogen-induced interfacial polarization potential is closely correlated with the microstructure of ferroelectric thin films and the enhancement of this interfacial polarization potential is mainly attributed to the high dielectric constant of amorphous ferroelectric thin films. A simple hydrogen interface-blocking model is also presented to explain this interesting phenomenon.

Effect of Temperature on the Electrical and Gas Sensing Properties of Polyaniline and Multiwall Carbon Nanotube Doped Polyaniline Composite Thin Films

2011 ◽  
Vol 254 ◽  
pp. 167-170 ◽  
Author(s):  
Subodh Srivastava ◽  
Sumit Kumar ◽  
Vipin Kumar Jain ◽  
Y.K. Vijay
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Gas Sensing ◽  
Hydrogen Gas ◽  
Composite Thin Film ◽  
Effect Of Temperature ◽  
Multiwall Carbon Nanotube ◽  
Film Sensor ◽  
Composite Thin Films ◽  
Pani Composite

In the present work we have reported the effect of temperature on the gas sensing properties of pure Polyaniline (PANI) and Multiwall carbon nanotube (MWNT) doped PANI composite thin film based chemiresistor type gas sensors for hydrogen gas sensing application. PANI and MWNT doped PANI composite were synthesized by in situ chemical oxidative polymerization of aniline using ammonium persulfate in an acidic medium. The thin sensing film of chemically synthesized PANI and MWNT doped PANI composite were deposited onto finger type Cu-interdigited electrodes using spin cast technique to prepared chemiresistor type gas sensor. The electrical properties of these composite thin films were characterized by I-V measurements as function of temperature. The I-V measurement revealed that conductivity of composite thin films increased as the temperature increased. The changes in resistance of the composite thin film sensor were utilized for detection of hydrogen gas. It was observed that at room temperature, MWNT doped PANI composite sensor shows higher response value and sensitivity with good repeatability in comparison to pure PANI thin film sensor. It was also observed that both PANI and MWNT doped PANI composite thin film based sensors showed unstable behavior as the temperature increased. The surface morphology of these composite thin films has also been characterized by scanning electron microscopy (SEM) measurement.

Hydrogen Gas Sensing Characterizations Based on Nanocrystalline SnO2 Thin Films Grown on SiO2/Si and Al2O3 Substrates

2017 ◽  
Vol 268 ◽  
pp. 244-248
Author(s):  
Abu Hassan Haslan ◽  
Imad Hussein Kadhim
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Gas Sensing ◽  
Sol Gel ◽  
Hydrogen Gas ◽  
Rutile Structure ◽  
Nanoparticle Distribution ◽  
Si Substrates ◽  
Coating Method ◽  
Different Temperatures

High-quality nanocrystalline (NC) SnO2 thin films were grown on SiO2/Si and Al2O3 substrates using sol–gel spin coating method. The structural properties, surface morphologies and gas sensing properties of the NC SnO2 were investigated. XRD measurements showed a tetragonal rutile structure and the diffraction peaks for NC SnO2 thin films grown on Al2O3 substrates outperformed those of NC SnO2 films grown on SiO2/Si substrates. The surface morphology of the annealed SnO2 thin films at 500 °C appeared as polycrystalline with uniform nanoparticle distribution. Hydrogen (H2) gas sensing performance of the NC SnO2 was examined for H2 concentrations ranging from 150 ppm to 1000 ppm at different temperatures (room temperature, 75 and 125 °C) for over 50 min. The room temperature sensitivities for H2 gas sensors based on NC SnO2 thin films grown on Al2O3 and SiO2/Si substrates was 2570% and 600%, respectively upon exposure to 1000 ppm of H2 gas. While the sensitivity values at 125 °C increased to 9200% and 1950%, respectively.

Structure of Hydrogen Gas Sensing TiO2 Thin Films Prepared by Sol-Gel Method and their Comparison with Magnetron Sputtered Films

2013 ◽  
Vol 543 ◽  
pp. 293-296 ◽  
Author(s):  
G. Plesch ◽  
A.A. Haidry ◽  
M. Gregor ◽  
P. Durina ◽  
J. Gregus ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Gas Sensing ◽  
Sol Gel ◽  
Rutile Phase ◽  
Hydrogen Gas ◽  
Gel Method ◽  
Sensing Properties ◽  
Sol Gel Method ◽  
Coating Method

TiO2thin films with a thickness of about 150 nm were deposited by spin coating method on sapphire substrate from a sol-gel system. The hydrogen sensing properties of TiO2films annealed at various temperatures were studied and correlated with their structure, optical and electrical properties. The annealing temperatures in the range of 600 800 °C lead to anatase films with a roughness in the range of 0.6 0.9 nm. Their sensitivity towards hydrogen is low. The thin films annealed at temperatures in the range 900 1000 °C consist of rutile phase and their roughness increased to 11.7 13.5 nm. They showed good hydrogen sensitivity with optimal operating temperature 200 250 °C. The structure and sensing properties of the prepared films are compared with those synthesized with magnetron sputtering. The maximum of sensitivity was measured on the thin films with diameter of the grains about 100 nm in both cases, i.e. on thin films prepared by sol-gel method as well as on thin films prepared by magnetron sputtering. The maximum sensitivity correlates with the diameter of the grains and dont depend on the allotropy of the titanium dioxide anatase or rutile.

Ferroelectric Thin Films for Microactuator Applications

1991 ◽  
Vol 243 ◽  
Author(s):  
Jiayu Chen ◽  
K. R. Udayakumar ◽  
Keith G. Brooks ◽  
L. Eric. Cross
Keyword(s):  
Thin Films ◽  
Laser Interferometer ◽  
Breakdown Strength ◽  
Sol Gel ◽  
Dielectric Constants ◽  
Ferroelectric Thin Films ◽  
Electromechanical Properties ◽  
High Dielectric

AbstractFerroelectric thin films of PZT and PMN-PT were fabricated by the solgel spin-on technique. The films show high dielectric constants, polarization and breakdown strength values. Using a laser interferometer (ultradilatometer), the piezoelectric and electrostrictive coefficients of the films were measured. The results indicate that the sol-gel derived ferroelectric thin films have good electromechanical properties and can be used in rnicroactuator applications.

Characterization and hydrogen gas sensing properties of TiO2 thin films prepared by sol–gel method

2012 ◽  
Vol 259 ◽  
pp. 270-275 ◽  
Author(s):  
Azhar Ali Haidry ◽  
Jarmila Puskelova ◽  
Tomas Plecenik ◽  
Pavol Durina ◽  
Jan Gregus ◽  
...  
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
Sol Gel ◽  
Hydrogen Gas ◽  
Tio2 Thin Films ◽  
Gel Method ◽  
Sensing Properties ◽  
Sol Gel Method ◽  
Gas Sensing Properties

Metal-Semiconductor-Insulator-Metal Structure Field-Effect Transistors Based on Zinc Oxides and Doped Ferroelectric Thin Films

2014 ◽  
Vol 1633 ◽  
pp. 131-137 ◽  
Author(s):  
Ze Jia ◽  
Jianlong Xu ◽  
Xiao Wu ◽  
Mingming Zhang ◽  
Naiwen Zhang ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Zinc Oxide ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Sol Gel ◽  
Drain Current ◽  
Metal Structure ◽  
Ferroelectric Materials ◽  
Ferroelectric Thin Films

ABSTRACTDifferent ferroelectric thin films and their related Metal-Semiconductor-Insulator-Metal (MSIM) structures include zinc oxide (ZnO) are studied, which can be utilized in back-gated ferroelectric field-effect transistors (FETs). The most ideal zinc oxide (ZnO) thin film prepared by sol-gel method are obtained under the pyrolysis temperature of 400°C and the annealing temperature of 600°C. The asymmetric or symmetric current-voltage characteristics of the heterostructures with ZnO are exhibited depending on different ferroelectric materials in them. The curves of drain current versus gate voltage for MSIM-structure FETs are investigated, in which obvious counterclockwise loops and a drain current switching ratio up to two orders of magnitude ate observed due to the modulation effect of remnant polarization on the channel resistance. The results also indicate the positive influences of impurity atom substitution in bismuth ferrite thin film for the MSIM-structure FETs.

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