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Fu-hsing Lu - One of the best experts on this subject based on the ideXlab platform.
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a facile growth control of perovskite srtio3 thin films by tailoring surface morphologies of tin seeding layers in the hydrothermal Galvanic Couple synthesis
Thin Solid Films, 2019Co-Authors: Huanping Teng, Fu-hsing LuAbstract:Abstract Growth control of cubic perovskite structure strontium titanate (SrTiO3) thin films was facilely achieved by tailoring surface morphologies of the TiN seeding layer in the hydrothermal-Galvanic Couple (HT-GC) synthesis. Two types of TiN thin films with pyramidal (P-TiN) and granular (G-TiN) surface morphologies were deposited on Si substrates by sputtering. The TiN-coated Si working electrodes were then directly connected to the Pt counter electrode without applying any external power source and soaked in 0.1 M Sr(CH3COOH)2 mixed with 2 M NaOH at 80 °C for 1–60 min. Significant Galvanic currents were detected during the HT-GC synthesis. Directional oriented cubic SrTiO3 thin films grew over the two types of highly preferred oriented TiN seeding layers. The growth kinetics of SrTiO3 was deduced by fitting the coverage of the oxide over the two types of TiN at different reaction times to a modified Avrami equation. It was shown that Galvanic currents, relative peak integrated intensities, and growth rates of SrTiO3 over the P-TiN were much higher than those on the G-TiN, while the grain sizes of SrTiO3 over the P-TiN were smaller. The faceted surfaces with fewer phase boundaries for P-TiN could yield a different rate-limiting step during the HT-GC synthesis and enhance significantly the growth of the oxide. This facile growth control could also be applied to similar perovskite oxide/conductive nitride systems.
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a facile method to control grain sizes of barium strontium titanate films on tin si in the hydrothermal Galvanic Couple synthesis
Ceramics International, 2017Co-Authors: Pei-hsuan Chan, Hsunshu Chan, Fu-hsing LuAbstract:Abstract Barium strontium titanate (BST) thin films, exhibiting many dielectric applications, were synthesized over TiN seeding layers by varying simply the total concentration of solutions in the hydrothermal-Galvanic synthesis. The BST films with different grain sizes were achieved by this facile control. The reaction concentrations were 2 M NaOH mixed with a fixed ratio of Ba(CH 3 COO) 2 and Sr(CH 3 COO) 2 in total concentrations of 0.01–1 M. X-ray diffraction patterns show that cubic BST possessed the same preferred orientation as the TiN seeding layer, indicating a directionally oriented growth. Field-emission scanning electron microscopy reveals spherical-particulate microstructures of the BST films with a single layer. Morphologies and grain sizes of BST films could be tailored by varying the total concentrations. As the total concentration of the solution was above a critical concentration, relative intensity, averaged grain size, and thickness of the BST increased rapidly first and then decreased gradually. This is mainly due to that grain growth was more prominent at lower total concentrations, leading to lager grain sizes and thicknesses of the BST films. On the other hand, nucleation predominates at higher concentrations, yielding smaller grain sizes and thicknesses of the films. Satisfactory dielectric results of the films were obtained by the synthesizing technique. The dielectric tunability could reach about 90% for BST in a total concentration of 0.035 M. The facile control of grain sizes for the BST films may bring in more promising technological applications.
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synthesis and formation mechanisms of bazro3 thin films prepared on zrn coated substrates by a low temperature hydrothermal Galvanic Couple method
Thin Solid Films, 2016Co-Authors: Huanping Teng, Hsiaohung Wu, Fu-hsing LuAbstract:Abstract Barium zirconate (BaZrO3; BZO) films exhibiting superior physical and chemical properties were synthesized over ZrN-coated Si substrates by a low temperature hydrothermal–Galvanic Couple method. Firstly, ZrN thin films were deposited onto Si by unbalanced magnetron sputtering. Subsequently, the ZrN-coated Si substrates were soaked in 0.5 M Ba(OH)2 mixed with various molar concentrations of NaOH at 90 °C for different reaction times by aid of a Galvanic Couple setup. Although no external power sources were applied, pronounced Galvanic currents were detected during the synthesis and revealed a very different plateau behavior. X-ray diffraction patterns show that cubic crystalline BZO films were formed on ZrN/Si in highly alkaline solutions for sufficient reaction time. Amorphous nano-layered oxides were present at lower-pH solutions. Aided by Galvanic effects, more OH− ions in the solution and longer reaction time would facilitate formation of a dense crystalline BZO. Reaction routes and formation mechanisms of the BZO films have been proposed.
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influence of sr 2 concentrations on growth of srtio3 thin films synthesized by hydrothermal Galvanic Couple method
Thin Solid Films, 2014Co-Authors: Yuhsiang Tsai, Yuchih Chieh, Fu-hsing LuAbstract:Abstract This work aims to explore the effects of Sr + 2 concentrations on the growth of SrTiO 3 thin films synthesized by the hydrothermal–Galvanic Couple method. The syntheses were conducted on the TiN/Si substrates in 2 M NaOH solutions consisting of various Sr + 2 concentrations at 80 °C. Cubic SrTiO 3 films were formed at Sr + 2 concentrations above 0.0004 M. Epitaxial-like growth of the SrTiO 3 films was found over the TiN underlayer at such various Sr + 2 concentrations. The relative diffraction peak intensity, the grain size, and the thickness of the obtained SrTiO 3 films first increased rapidly, then reached the maximum, and decreased gradually afterwards with increasing the Sr + 2 concentrations. The grain size and the thickness of the films would reach the maximum at 0.001 M [Sr + 2 ]. Nanograins of the films were present at high Sr + 2 concentrations. The growth kinetics of the films was determined by a modified Avrami–Erofe'ev equation. Nucleation governs the formation of SrTiO 3 at high Sr + 2 concentrations, leading to the nanograins. Grain growth predominates at low Sr + 2 concentrations, yielding the large grains. Moreover, both the dielectric constant and the dielectric loss of the obtained SrTiO 3 films increased with decreasing the Sr + 2 concentrations.
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Influence of Sr+ 2 concentrations on growth of SrTiO3 thin films synthesized by hydrothermal–Galvanic Couple method
Thin Solid Films, 2014Co-Authors: Yuhsiang Tsai, Yuchih Chieh, Fu-hsing LuAbstract:Abstract This work aims to explore the effects of Sr + 2 concentrations on the growth of SrTiO 3 thin films synthesized by the hydrothermal–Galvanic Couple method. The syntheses were conducted on the TiN/Si substrates in 2 M NaOH solutions consisting of various Sr + 2 concentrations at 80 °C. Cubic SrTiO 3 films were formed at Sr + 2 concentrations above 0.0004 M. Epitaxial-like growth of the SrTiO 3 films was found over the TiN underlayer at such various Sr + 2 concentrations. The relative diffraction peak intensity, the grain size, and the thickness of the obtained SrTiO 3 films first increased rapidly, then reached the maximum, and decreased gradually afterwards with increasing the Sr + 2 concentrations. The grain size and the thickness of the films would reach the maximum at 0.001 M [Sr + 2 ]. Nanograins of the films were present at high Sr + 2 concentrations. The growth kinetics of the films was determined by a modified Avrami–Erofe'ev equation. Nucleation governs the formation of SrTiO 3 at high Sr + 2 concentrations, leading to the nanograins. Grain growth predominates at low Sr + 2 concentrations, yielding the large grains. Moreover, both the dielectric constant and the dielectric loss of the obtained SrTiO 3 films increased with decreasing the Sr + 2 concentrations.
Pei-hsuan Chan - One of the best experts on this subject based on the ideXlab platform.
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a facile method to control grain sizes of barium strontium titanate films on tin si in the hydrothermal Galvanic Couple synthesis
Ceramics International, 2017Co-Authors: Pei-hsuan Chan, Hsunshu Chan, Fu-hsing LuAbstract:Abstract Barium strontium titanate (BST) thin films, exhibiting many dielectric applications, were synthesized over TiN seeding layers by varying simply the total concentration of solutions in the hydrothermal-Galvanic synthesis. The BST films with different grain sizes were achieved by this facile control. The reaction concentrations were 2 M NaOH mixed with a fixed ratio of Ba(CH 3 COO) 2 and Sr(CH 3 COO) 2 in total concentrations of 0.01–1 M. X-ray diffraction patterns show that cubic BST possessed the same preferred orientation as the TiN seeding layer, indicating a directionally oriented growth. Field-emission scanning electron microscopy reveals spherical-particulate microstructures of the BST films with a single layer. Morphologies and grain sizes of BST films could be tailored by varying the total concentrations. As the total concentration of the solution was above a critical concentration, relative intensity, averaged grain size, and thickness of the BST increased rapidly first and then decreased gradually. This is mainly due to that grain growth was more prominent at lower total concentrations, leading to lager grain sizes and thicknesses of the BST films. On the other hand, nucleation predominates at higher concentrations, yielding smaller grain sizes and thicknesses of the films. Satisfactory dielectric results of the films were obtained by the synthesizing technique. The dielectric tunability could reach about 90% for BST in a total concentration of 0.035 M. The facile control of grain sizes for the BST films may bring in more promising technological applications.
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hydrothermal Galvanic Couple synthesis of directionally oriented batio3 thin films on tin coated substrates
Thin Solid Films, 2013Co-Authors: Chiajung Yang, Pei-hsuan Chan, Diyou Tsai, Chutsun Wu, Fu-hsing LuAbstract:Abstract BaTiO 3 films were synthesized on TiN-coated Si substrate below 100 °C by a hydrothermal–Galvanic Couple technique in barium contained alkaline solutions. X-ray diffraction and electron backscatter diffraction results show that the BaTiO 3 thin films were directionally oriented grown on the TiN/Si substrates, i.e., (111) BaTiO 3 over (111) TiN. The surface morphologies revealed that BaTiO 3 nucleated and grew over the TiN surface with a single layer. From kinetic analyses, the growth rates of BaTiO 3 films prepared by the hydrothermal–Galvanic Couple technique were faster than a hydrothermal method. The Galvanic effects were confirmed by investigating the induced currents and energies. The Galvanic currents were generated and controlled by both the dissolution of TiN and the formation of BaTiO 3 . The output electric energies increased rapidly with the reaction time and leveled off at the full coverage of BaTiO 3 .
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preparation of ba x sr 1 x tio 3 thin films on tin si by a novel hydrothermal Galvanic Couple method
IEEE International Nanoelectronics Conference, 2010Co-Authors: Pei-hsuan Chan, Fu-hsing LuAbstract:Ba x Sr 1−x TiO 3 (BST) thin films have been prepared on TiN/Si by a novel hydrothermal-Galvanic Couple method at temperatures below 100°C. The TiN/Si specimens were immersed in Ba(CH 3 COO) 2 , Sr(CH 3 COO) 2 , and NaOH alkaline solutions with different concentration ratio. X-ray diffraction results show that cubic BST films were successfully formed on TiN/Si substrates by the hydrothermal-Galvanic Couple method. The growth rate of crystalline BST using the hydrothermal-Galvanic Couple method is much faster than the conventional hydrothermal method. The composition of BST thin films derived by the hydrothermal-Galvanic Couple method depends on the concentration ratio of Ba(CH 3 COO) 2 and Sr(CH 3 COO) 2 . Field-emission scanning electron microscopy reveals spherical-particulate microstructure of BST films. The microstructure and crystalline of BST depend on the concentration of Ba2+ and Sr2+ in the solutions. Influences of Ba/Sr ratios on the growth behavior of BST films are investigated.
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Preparation of Ba x Sr 1−x TiO 3 thin films on TiN/Si by a novel hydrothermal-Galvanic Couple method
2010 3rd International Nanoelectronics Conference (INEC), 2010Co-Authors: Pei-hsuan Chan, Fu-hsing LuAbstract:Ba x Sr 1−x TiO 3 (BST) thin films have been prepared on TiN/Si by a novel hydrothermal-Galvanic Couple method at temperatures below 100°C. The TiN/Si specimens were immersed in Ba(CH 3 COO) 2 , Sr(CH 3 COO) 2 , and NaOH alkaline solutions with different concentration ratio. X-ray diffraction results show that cubic BST films were successfully formed on TiN/Si substrates by the hydrothermal-Galvanic Couple method. The growth rate of crystalline BST using the hydrothermal-Galvanic Couple method is much faster than the conventional hydrothermal method. The composition of BST thin films derived by the hydrothermal-Galvanic Couple method depends on the concentration ratio of Ba(CH 3 COO) 2 and Sr(CH 3 COO) 2 . Field-emission scanning electron microscopy reveals spherical-particulate microstructure of BST films. The microstructure and crystalline of BST depend on the concentration of Ba2+ and Sr2+ in the solutions. Influences of Ba/Sr ratios on the growth behavior of BST films are investigated.
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Preparation of BaxSr1−xTiO3 thin films on TiN/Si by a novel hydrothermal-Galvanic Couple method
2010 3rd International Nanoelectronics Conference (INEC), 2010Co-Authors: Pei-hsuan Chan, Fu-hsing LuAbstract:BaxSr1-xTiO3(BST) thin films have been prepared on TiN/Si by a novel hydrothermal-Galvanic Couple method at temperatures below 100°C. The TiN/Si specimens were immersed in Ba(CH3COO)2, Sr(CH3COO)2, and NaOH alkaline solutions with different concentration ratio. X-ray diffraction results show that cubic BST films were successfully formed on TiN/Si substrates by the hydrothermal-Galvanic Couple method. The growth rate of crystalline BST using the hydrothermal-Galvanic Couple method is much faster than the conventional hydrothermal method. The composition of BST thin films derived by the hydrothermal-Galvanic Couple method depends on the concentration ratio of Ba(CH3COO)2 and Sr(CH3COO)2. Field-emission scanning electron microscopy reveals spherical-particulate microstructure of BST films. The microstructure and crystalline of BST depend on the concentration of Ba2+ and Sr2+ in the solutions. Influences of Ba/Sr ratios on the growth behavior of BST films are investigated.
Amar Prasad Yadav - One of the best experts on this subject based on the ideXlab platform.
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surface potential distribution over a zinc steel Galvanic Couple corroding under thin layer of electrolyte
Electrochimica Acta, 2007Co-Authors: Amar Prasad Yadav, Hideki Katayama, Kazuhiko Noda, Hiroyuki Masuda, Atsushi Nishikata, Tooru TsuruAbstract:In this study, surface potential and surface pH changes over a zinc/steel Galvanic Couple corroding in artificial seawater (ASW) at 60 and 90% RH have been investigated. The results from surface potential and surface pH measurements were substantiated by the surface observation of the corroded sample during and after the corrosion test. The potential difference over the zinc and steel surface in 90% RH was very low (less than 200 mV) showing that whole steel surface was under Galvanic protection. On the other hand, in 60% RH, after several days of corrosion the potential difference between the zinc coating and the steel surface was very high (more than 500 mV) and hence the Galvanic protection was limited to interface region. The X-ray analysis of the sample corroded in 60% RH has shown that the zinc corrosion products were deposited on the steel surface near the interface, the same region has shown a low pH compared to than in other part of the steel surface. This led to conclude that with the progress of corrosion, the coating surface of zinc coated steel acidifies by the hydrolysis reaction of the dissolved zinc ions, and the iron surface showed the alkalinity by the oxygen reduction reaction. Moreover, the parts of the steel surface covered with zinc corrosion products had developed relatively less noble potential than other parts indicating that zinc corrosion products took a role to protect the base steel against corrosion. It was assumed that this behavior was related to a combination of the water absorbing capability of zinc corrosion products and adsorption of zinc ion on the steel surface due to low pH.
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Surface potential distribution over a zinc/steel Galvanic Couple corroding under thin layer of electrolyte
Electrochimica Acta, 2007Co-Authors: Amar Prasad Yadav, Hideki Katayama, Kazuhiko Noda, Hiroyuki Masuda, Atsushi Nishikata, Tooru TsuruAbstract:In this study, surface potential and surface pH changes over a zinc/steel Galvanic Couple corroding in artificial seawater (ASW) at 60 and 90% RH have been investigated. The results from surface potential and surface pH measurements were substantiated by the surface observation of the corroded sample during and after the corrosion test. The potential difference over the zinc and steel surface in 90% RH was very low (less than 200 mV) showing that whole steel surface was under Galvanic protection. On the other hand, in 60% RH, after several days of corrosion the potential difference between the zinc coating and the steel surface was very high (more than 500 mV) and hence the Galvanic protection was limited to interface region. The X-ray analysis of the sample corroded in 60% RH has shown that the zinc corrosion products were deposited on the steel surface near the interface, the same region has shown a low pH compared to than in other part of the steel surface. This led to conclude that with the progress of corrosion, the coating surface of zinc coated steel acidifies by the hydrolysis reaction of the dissolved zinc ions, and the iron surface showed the alkalinity by the oxygen reduction reaction. Moreover, the parts of the steel surface covered with zinc corrosion products had developed relatively less noble potential than other parts indicating that zinc corrosion products took a role to protect the base steel against corrosion. It was assumed that this behavior was related to a combination of the water absorbing capability of zinc corrosion products and adsorption of zinc ion on the steel surface due to low pH.
Junxi Zhang - One of the best experts on this subject based on the ideXlab platform.
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electrochemical and svet studies on the typical polarity reversal of cu 304 stainless steel Galvanic Couple in cl containing solution with different ph
Electrochimica Acta, 2017Co-Authors: Qingzhao Ni, Junxi ZhangAbstract:Abstract The typical polarity reversal of the Cu–304 stainless steel Galvanic Couple (Cu–304SS GC) in Cl − - containing solution with different pH was investigated by open circuit potential (OCP), potentiodynamic polarization, and Galvanic current techniques in conjunction with scanning vibrating electrode technique (SVET) and scanning electron microscopy (SEM). The results showed that the change in pH of the solution has a significant effect on the corrosion behavior of 304SS. The typical polarity reversal occurs in Cu–304SS GC in Cl − solution with pH 0, in which the red copper is cathodic to 304SS, while in the solution with pH 6, 4, and 2 the red copper is anodic to 304SS. With the decrease in pH, the 304SS changes from the passive state to the activation state due to the dissolution of the passive film on the surface thereby facilitating the polarity reversal of the Cu–304SS GC.
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Electrochemical and SVET Studies on the Typical Polarity Reversal of Cu–304 Stainless Steel Galvanic Couple in Cl−-Containing Solution with Different pH
Electrochimica Acta, 2017Co-Authors: Qingzhao Ni, Junxi ZhangAbstract:Abstract The typical polarity reversal of the Cu–304 stainless steel Galvanic Couple (Cu–304SS GC) in Cl − - containing solution with different pH was investigated by open circuit potential (OCP), potentiodynamic polarization, and Galvanic current techniques in conjunction with scanning vibrating electrode technique (SVET) and scanning electron microscopy (SEM). The results showed that the change in pH of the solution has a significant effect on the corrosion behavior of 304SS. The typical polarity reversal occurs in Cu–304SS GC in Cl − solution with pH 0, in which the red copper is cathodic to 304SS, while in the solution with pH 6, 4, and 2 the red copper is anodic to 304SS. With the decrease in pH, the 304SS changes from the passive state to the activation state due to the dissolution of the passive film on the surface thereby facilitating the polarity reversal of the Cu–304SS GC.
Tooru Tsuru - One of the best experts on this subject based on the ideXlab platform.
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surface potential distribution over a zinc steel Galvanic Couple corroding under thin layer of electrolyte
Electrochimica Acta, 2007Co-Authors: Amar Prasad Yadav, Hideki Katayama, Kazuhiko Noda, Hiroyuki Masuda, Atsushi Nishikata, Tooru TsuruAbstract:In this study, surface potential and surface pH changes over a zinc/steel Galvanic Couple corroding in artificial seawater (ASW) at 60 and 90% RH have been investigated. The results from surface potential and surface pH measurements were substantiated by the surface observation of the corroded sample during and after the corrosion test. The potential difference over the zinc and steel surface in 90% RH was very low (less than 200 mV) showing that whole steel surface was under Galvanic protection. On the other hand, in 60% RH, after several days of corrosion the potential difference between the zinc coating and the steel surface was very high (more than 500 mV) and hence the Galvanic protection was limited to interface region. The X-ray analysis of the sample corroded in 60% RH has shown that the zinc corrosion products were deposited on the steel surface near the interface, the same region has shown a low pH compared to than in other part of the steel surface. This led to conclude that with the progress of corrosion, the coating surface of zinc coated steel acidifies by the hydrolysis reaction of the dissolved zinc ions, and the iron surface showed the alkalinity by the oxygen reduction reaction. Moreover, the parts of the steel surface covered with zinc corrosion products had developed relatively less noble potential than other parts indicating that zinc corrosion products took a role to protect the base steel against corrosion. It was assumed that this behavior was related to a combination of the water absorbing capability of zinc corrosion products and adsorption of zinc ion on the steel surface due to low pH.
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Surface potential distribution over a zinc/steel Galvanic Couple corroding under thin layer of electrolyte
Electrochimica Acta, 2007Co-Authors: Amar Prasad Yadav, Hideki Katayama, Kazuhiko Noda, Hiroyuki Masuda, Atsushi Nishikata, Tooru TsuruAbstract:In this study, surface potential and surface pH changes over a zinc/steel Galvanic Couple corroding in artificial seawater (ASW) at 60 and 90% RH have been investigated. The results from surface potential and surface pH measurements were substantiated by the surface observation of the corroded sample during and after the corrosion test. The potential difference over the zinc and steel surface in 90% RH was very low (less than 200 mV) showing that whole steel surface was under Galvanic protection. On the other hand, in 60% RH, after several days of corrosion the potential difference between the zinc coating and the steel surface was very high (more than 500 mV) and hence the Galvanic protection was limited to interface region. The X-ray analysis of the sample corroded in 60% RH has shown that the zinc corrosion products were deposited on the steel surface near the interface, the same region has shown a low pH compared to than in other part of the steel surface. This led to conclude that with the progress of corrosion, the coating surface of zinc coated steel acidifies by the hydrolysis reaction of the dissolved zinc ions, and the iron surface showed the alkalinity by the oxygen reduction reaction. Moreover, the parts of the steel surface covered with zinc corrosion products had developed relatively less noble potential than other parts indicating that zinc corrosion products took a role to protect the base steel against corrosion. It was assumed that this behavior was related to a combination of the water absorbing capability of zinc corrosion products and adsorption of zinc ion on the steel surface due to low pH.
