Hsin-Chun Lu - Academia.edu (original) (raw)

Papers by Hsin-Chun Lu

IEEE Transactions on Electron Devices, 2021

Heat generation in integrated circuits (ICs) has become a severe issue, which limits the utilizat... more Heat generation in integrated circuits (ICs) has become a severe issue, which limits the utilization of miniaturized semiconductor devices in high-density 3-D IC technologies. Herein, Al₂O₃ was doped in ZrO₂ thin films by plasma-enhanced atomic layer deposition (PEALD) to enhance their antiferroelectric (AFE) characteristics for highly reliable electrocaloric (EC) cooling applications. The cycling endurance in AFE behaviors of the Al:ZrO₂ thin films under a high electric field of 5 MV/cm was significantly improved because of the enlargement of the energy bandgap with high resistance in trap-induced leakage current. Hence, the reliability of the EC effect of the 1% Al:ZrO₂ thin film was examined with a negligible change in adiabatic temperature change (<inline-formula> <tex-math notation="LaTeX">$\Delta {T}$ </tex-math></inline-formula>) of 2.6% after a cycling endurance test of <inline-formula> <tex-math notation="LaTeX">$10^{{6}}$ </tex-math></inline-formula> cycles. With the competitive cycling reliabilities in AFE and EC behaviors, devices with optimized Al₂O₃-incorporated ZrO₂ thin films show significant potential for future nanoscale cooling systems in chip-level ICs.

Journal of Power Sources, 2020

Hybrid electrolyte lithium air battery is feasible with ambient humid air as feed. � Lithium ion ... more Hybrid electrolyte lithium air battery is feasible with ambient humid air as feed. � Lithium ion conductive membrane is made of lithium aluminum titanium phosphate. � Cobalt oxide/graphene is efficient air cathode with ORR and OER activities. � Optimal mass ratio of cobalt oxide to graphene is found to be 48:52.

Nanomaterials, 2020

A potent cathode catalyst of octahedral cobalt oxide (Co3O4) was synthesized onto graphene (GR) n... more A potent cathode catalyst of octahedral cobalt oxide (Co3O4) was synthesized onto graphene (GR) nanosheets via a two-step preparation method. The precursor cobalt solution reacted with GR during the initial hydrolysis step to form intermediates. A subsequent hydrothermal reaction promoted Co3O4 crystallinity with a crystalline size of 73 nm, resulting in octahedral particles of 100–300 nm in size. Scanning electron microscopy, Raman spectroscopy, and X-ray diffraction analysis confirmed the successful formation of the Co3O4/GR composite. This catalyst composite was sprayed onto a carbon cloth to form a cathode for the hybrid electrolyte lithium-air battery (HELAB). This catalyst demonstrated improved oxygen reduction and oxygen evolution capabilities. The HELAB containing this catalyst showed a higher discharge voltage and stable charge voltage, resulting in a 34% reduction in overall over-potential compared to that without the Co3O4/GR composite. The use of saturated LiOH in 11.6 M...

INTRODUCTION EXPERIMENTAL PROCEDURE Starting materials 44 Preparation of titania sol 44 ill Prepa... more INTRODUCTION EXPERIMENTAL PROCEDURE Starting materials 44 Preparation of titania sol 44 ill Preparation of titania sol-barium methoxide mixture 44 Preparation and characterization of barium titanates 45 RESULTS AND DISCUSSION 46 Influence of preparation parameters on the stability of the titania sols and titania sol-barium methoxide mixture 46 BaTisOii (1:5 compound) 49 Ba2Ti9O20 (2:9 compound) 53 CONCLUSION 59 REFERENCES CITED 60 PAPER IL CHARACTERIZATION OF THE GROWTH OF SOL-GEL DERIVED Ba-Ti-O THIN FILMS BY LASER RAMAN SPECTROSCOPY 63 ABSTRACT INTRODUCTION EXPERIMENTAL DETAILS Thin film preparation In situ Raman cell Characterization of thin film 71 RESULTS 75 DISCUSSION 85 iv Enhancement mechanism for Raman signal 85 Variation of the intensity of Raman spectrum during in situ measurement CONCLUSION REFERENCES CITED PAPER III. PREPARATION AND CHARACTERIZATION OF SOL-GEL DERIVED Ba2Ti9O20 AND BaTisOn THIN FILMS 92

Nano Energy, 2019

A novel coral-like perovskite nanostructured layer was grown on a compact perovskite foundation l... more A novel coral-like perovskite nanostructured layer was grown on a compact perovskite foundation layer by the facile surface modification with dimethylformamide/isopropanol (DMF/IPA) as co-solvent. Surface morphological characterizations with SEM and XRD analyses revealed a growing mechanism of the new morphology, which was composed of the perovskite decomposition and recrystallization, excessive-PbI 2 extraction, and sequential formation of coral-like nanostructured perovskite layer. The coral-like perovskite nanostructures resulted in significant light scattering, enhancing the light-harvesting efficiency, and thus augmenting the photocurrent density. Moreover, the geometric configuration of the perovksite solar cells was changed from planar to bulk heterojunction, which results in the acceleration of charge separation and extraction due to the high surface area at the interface between the obtained perovskite and hole-transport layers. The optimal perovskite solar cell exhibited an impressive power conversion efficiency (PCE) of 19.47%, as compared to that of the pristine cell (17.19%).

Thin Solid Films, 2009

Cuprous oxide (Cu 2 O) and cupric oxide (CuO) thin films were deposited on glass substrates at di... more Cuprous oxide (Cu 2 O) and cupric oxide (CuO) thin films were deposited on glass substrates at different oxygen partial pressures by direct-current reactive magnetron sputtering of pure copper target in a mixture of argon and oxygen gases. Oxygen partial pressure was found to be a crucial parameter in controlling the phases and, thus, the physical properties of the deposited copper oxide thin films. Single-phase Cu 2 O thin films with cubic structure were obtained at low oxygen partial pressure between 0.147 Pa and 0.200 Pa while higher oxygen partial pressure promoted the formation of CuO thin films with base-centered monoclinic structure. Polycrystalline Cu 2 O thin films deposited with oxygen partial pressure at 0.147 Pa possessed the lowest p-type resistivity of 1.76 Ω cm as well as an optical band gap of 2.01 eV. On the other hand, polycrystalline CuO thin films deposited with oxygen partial pressure at 0.320 Pa were also single phase but showed a n-type resistivity of 0.19 Ω cm along with an optical band gap of 1.58 eV.

Procedia Technology, 2017

Amorphous indium gallium zinc oxide (a-IGZO) thin film transistor (TFT) biosensors were fabricate... more Amorphous indium gallium zinc oxide (a-IGZO) thin film transistor (TFT) biosensors were fabricated by surface modification of the a-IGZO TFT devices and the immobilization of Creatine Kinase (CK-MM) antibodies on the a-IGZO TFT devices. When the fabricated CK-MM a-IGZO TFT biosensors were used to detect CK-MM in the sample, both the field effect mobility and the Ion/Ioff ratio of the a-IGZO TFT devices were found to increase. These results indicate the potential applications for the developed a-IGZO TFT devices in biosensing.

Energy, 2017

The objectives of this work are to prepare and characterize poly[2,2 0-m-(phenylene)-5,5 0-bibenz... more The objectives of this work are to prepare and characterize poly[2,2 0-m-(phenylene)-5,5 0-bibenzimidazole]/graphene oxide (PBI/GO) solid electrolyte for direct alcohol alkaline fuel cell (DAAFC) applications. GO nanosheets are coated onto a PBI surface using a spin coater to construct the PBI/GO composite membrane. The PBI/GO composite membrane exhibits an ionic conductivity of 2.53 Â 10 À2 S cm À1 at 80 C, which is improved by 72e93% when compared with the pure PBI membrane. In addition, the methanol permeability is reduced by 18e25% by incorporating GO onto the PBI top surface. The peak power density (P max) of the PBI/GO electrolyte reaches 200 mW cm À2 when using alkaline methanol as fuel with Pt-based catalysts, or 120 mW cm À2 when fed with an ethanol and alkaline solution mixture at 80 C. Replacing the Pt-based catalysts with Hypermec™ catalysts resulted in P max of 40 and 100 mW cm À2 , for methanol and ethanol fuel cells, respectively. These superior DAAFC power outputs are ascribed to the improved anion conduction of the KOH doped GO and the suppressed methanol cross-over from high aspect ratio GO as the alcohol barrier layer.

Materials Chemistry and Physics, 2015

Abstract Indium gallium zinc oxide (InGaZnO 4 , IGZO) has attracted explosive growth in investiga... more Abstract Indium gallium zinc oxide (InGaZnO 4 , IGZO) has attracted explosive growth in investigations over the last decades as an important material in the thin-film transistor. In this study, the various nitrate precursors, including indium nitrate, gallium nitrate, and zinc nitrate, were prepared from the various metals dissolved in nitric acid. Then, we used these nitrate precursors to synthesize the IGZO precursor powder by the multistep co-precipitation method. The synthesis parameters of the co-precipitation method, such as reaction temperature, pH value and reaction time, were controlled precisely to prepare the high quality IGZO precursor powder. Finally, IGZO precursor powder was calcined at 900 °C. Then, the microstructure, the crystalline structure, the particle size distribution and specific surface area of calcined IGZO precursor powder were characterized by electron transmission microscopy, X-ray diffraction technique, dynamic light scattering method and the surface area and porosimetry analyzer, respectively. The relative density of IGZO tablet sintered at 1200 °C for 12 h is as high as 97.30%, and it showed highly InGaZnO 4 crystalline structure and the large grain size. The IGZO nanoparticles developed in our study has the potential for the high quality target materials used in the application of electronic devices.

2010 3rd International Nanoelectronics Conference (INEC), 2010

Abstract This paper presents the preparation of piezoelectric lead zirconium titanate (PZT) thick... more Abstract This paper presents the preparation of piezoelectric lead zirconium titanate (PZT) thick films and the fabrication of PZT surface acoustic waves (SAW) devices with sub-micron IDT electrodes by the micro-powder-sol-gel method. The utilization of these PZT SAW ...

2010 3rd International Nanoelectronics Conference (INEC), 2010

Abstract This paper presents the synthesis of antimony-doped tin oxide (ATO) nanorods by calcinin... more Abstract This paper presents the synthesis of antimony-doped tin oxide (ATO) nanorods by calcining coprecipitated precursors at high temperature with sodium silicate and sodium chloride additives. From the experimental results, it is found that in order to produce ...

Thin Solid Films, 1992

The isothermal growth kinetics of sol-gel derived BaTi,O,, thin films has been studied by laser R... more The isothermal growth kinetics of sol-gel derived BaTi,O,, thin films has been studied by laser Raman spectroscopy. Thin films of the precursors were spin coated on silicon wafers with platinum or gold overlayers. The films were then annealed isothermally, and Raman spectra were recorded in situ. The time-dependent intensity changes of the Raman bands could be analyzed in terms of Avrami models. The interaction of the BaTi,O,, film with the platinum or gold overlayers during heat treatment apparently increased the Raman intensity by a factor of about 100.

2008 2nd IEEE International Nanoelectronics Conference, 2008

Nano-sized powders of transparent conductive aluminum-doped zinc oxide (AZO) have been successful... more Nano-sized powders of transparent conductive aluminum-doped zinc oxide (AZO) have been successfully prepared by electrolysis-modified co-precipitation method. By adding ammonium hydroxide into the precursor solution prepared by electrolytic dissolution of zinc metal in a buffered electrolyte solution of nitric acid and ammonium nitrate with adequate addition of aluminum nitrate, co-precipitate precursors of AZO with particle size between 30 to 60

2008 2nd IEEE International Nanoelectronics Conference, 2008

Nano-powders of p-type transparent conductive copper aluminum oxide (CAO) have been successfully ... more Nano-powders of p-type transparent conductive copper aluminum oxide (CAO) have been successfully synthesized by co-precipitation method. By adding sodium hydroxide into the mixed solution of copper chloride and aluminum chloride, co-precipitate precursors of CAO with particle size around 50-60 nm were produced. After washing, filtering, and drying of the co-precipitates, nano-powders of CuAlO 2 were produced when the dried co-precipitate precursors were calcined at temperature above 1100 ℃. By aging at pH=3.5 for six hours and co-precipitating at pH=8.0, the atomic ratio of Cu/Al of the nano-powders can be maintained throughout the synthesis. After calcining at 1200℃ in air for 4 hours, the CAO co-precipitate precursors totally transformed into nano-powders of CuAlO 2 with crystal size around 64 nm. Continued calcining at 1200℃ above 4 hours led to the decomposition of CuAlO 2 into nano-powders of CuAl 2 O 4 and volatile CuO with no significant change in crystal size. Finally, it was found that by calcining under inert atmosphere, the decomposition of CuAlO 2 could be suppressed at the expense of decreasing its crystallinity. I.

Nano/Micro Engineered and Molecular Systems, 2009

In this paper, we studied a method to reduce the compressive strain in the InGaN/GaN multiple qua... more In this paper, we studied a method to reduce the compressive strain in the InGaN/GaN multiple quantum well (MQW) structures by inserting a strain relief layer between n-GaN and MQWs. The improvements in the interface quality and the optical properties were investigated by photoluminescence (PL) and high-resolution X-ray diffraction (HRXRD) analysis. The samples showed S-shaped emission energy peak and stronger

Vacuum, 2008

Transparent conducting ITO thin film has been widely used as anode material in OLEDs due to its g... more Transparent conducting ITO thin film has been widely used as anode material in OLEDs due to its good optical transparency, low electrical resistivity, ease of patterning, high work function and efficient hole injection properties. The interface between ITO and organic layer in OLED device is thus important and can influence the electrical and luminescent properties. In this report, ITO substrates were treated with 20% H 3 PO 4 solution. The corresponding changes in crystalline morphology were studied by X-ray diffraction. X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) were performed at w10 À9 Torr to study the work function and the valence band structure of ITO substrates. It was found that work function became slightly lower after the treatment, probably caused by the formation of metal complex compounds and metal hydroxides. The binding energy of In 3d 5/2 shifted from 444.6 to 445.3 eV. This shifting was referred to the formation of In-OH bonding. It would be easier to provide electron by In-OH bonding than by In-O-In or Sn-O-Sn when photons reached ITO surface. The interface between ITO and CuPc was improved through polar surface and less aggregation. In addition, the OLED devices exhibited improved performance in both external quantum efficiency and luminescence efficiency.

Surface and Coatings Technology, 2013

Abstract Gallium-doped magnesium zinc oxide (GMZO) thin films were deposited onto glass substrate... more Abstract Gallium-doped magnesium zinc oxide (GMZO) thin films were deposited onto glass substrates using RF magnetron sputtering using GMZO ceramic targets under different sputtering conditions. The substrate temperature and deposition pressure effects on the structural, electrical and optical properties of the GMZO thin film were investigated. Transparent conductive GMZO thin films were demonstrated in this study to possess a wurtzite structure, average transmittance above 80% in the 400 nm and 800 nm wavelength range with a low resistivity of 1.62 × 10 − 3 Ω cm when deposited onto glass substrates using RF magnetron sputtering.

Surface and Coatings Technology, 2013

Indium tin oxide (ITO) thin films were fabricated by spin-coating the coating solutions containin... more Indium tin oxide (ITO) thin films were fabricated by spin-coating the coating solutions containing solvothermally synthesized ITO nanoparticles on glass substrates with subsequent low temperature curing. Characterizations of the solvothermally synthesized nanoparticles confirmed that crystalline nano-sized ITO nanoparticles with crystal grain size between 17 and 20 nm were successfully obtained by solvothermal treatment of the precursor coprecipitates. By dispersing the solvothermally synthesized ITO nanoparticles in methanol, coating solutions containing well dispersed ITO nanoparticles for subsequent ITO thin film coating were prepared. It was demonstrated that the thin films fabricated by spin-coating the ITO nanoparticle coating solutions on glass substrates followed by 413.15 K heat curing under nitrogen atmosphere for 30 min were transparent conductive ITO thin films with a sheet resistance of 1.9 × 10 5 Ω/□.

Physica B: Condensed Matter, 2009

Abstract p-Type aluminum–nitrogen (Al–N) co-doped zinc oxide (ZnO) thin films were deposited on g... more Abstract p-Type aluminum–nitrogen (Al–N) co-doped zinc oxide (ZnO) thin films were deposited on glass substrate at 300 °C by RF reactive magnetron sputtering using an aluminum-doped zinc oxide (2.4 wt%Al2O3) target and N2 reactive gas. In addition, the effect of N2 reactive gas on the electrical and structural properties of Al–N co-doped ZnO thin films was also investigated. It was found that p-type Al–N co-doped ZnO thin films could be obtained only when the volume ratio of N2 in the N2-containing Ar working gas exceeded 10%. p-Type Al–N co-doped ZnO thin films with a minimum resistivity of 0.141 Ω cm, a p-type carrier concentration of 5.84×1018 cm−3, and a Hall mobility of 3.68 cm2/V s were obtained in this study when the volume ratio of N2 in the working gas was 30%.

IEEE Transactions on Electron Devices, 2021

Heat generation in integrated circuits (ICs) has become a severe issue, which limits the utilizat... more Heat generation in integrated circuits (ICs) has become a severe issue, which limits the utilization of miniaturized semiconductor devices in high-density 3-D IC technologies. Herein, Al₂O₃ was doped in ZrO₂ thin films by plasma-enhanced atomic layer deposition (PEALD) to enhance their antiferroelectric (AFE) characteristics for highly reliable electrocaloric (EC) cooling applications. The cycling endurance in AFE behaviors of the Al:ZrO₂ thin films under a high electric field of 5 MV/cm was significantly improved because of the enlargement of the energy bandgap with high resistance in trap-induced leakage current. Hence, the reliability of the EC effect of the 1% Al:ZrO₂ thin film was examined with a negligible change in adiabatic temperature change (<inline-formula> <tex-math notation="LaTeX">$\Delta {T}$ </tex-math></inline-formula>) of 2.6% after a cycling endurance test of <inline-formula> <tex-math notation="LaTeX">$10^{{6}}$ </tex-math></inline-formula> cycles. With the competitive cycling reliabilities in AFE and EC behaviors, devices with optimized Al₂O₃-incorporated ZrO₂ thin films show significant potential for future nanoscale cooling systems in chip-level ICs.

Journal of Power Sources, 2020

Hybrid electrolyte lithium air battery is feasible with ambient humid air as feed. � Lithium ion ... more Hybrid electrolyte lithium air battery is feasible with ambient humid air as feed. � Lithium ion conductive membrane is made of lithium aluminum titanium phosphate. � Cobalt oxide/graphene is efficient air cathode with ORR and OER activities. � Optimal mass ratio of cobalt oxide to graphene is found to be 48:52.

Nanomaterials, 2020

A potent cathode catalyst of octahedral cobalt oxide (Co3O4) was synthesized onto graphene (GR) n... more A potent cathode catalyst of octahedral cobalt oxide (Co3O4) was synthesized onto graphene (GR) nanosheets via a two-step preparation method. The precursor cobalt solution reacted with GR during the initial hydrolysis step to form intermediates. A subsequent hydrothermal reaction promoted Co3O4 crystallinity with a crystalline size of 73 nm, resulting in octahedral particles of 100–300 nm in size. Scanning electron microscopy, Raman spectroscopy, and X-ray diffraction analysis confirmed the successful formation of the Co3O4/GR composite. This catalyst composite was sprayed onto a carbon cloth to form a cathode for the hybrid electrolyte lithium-air battery (HELAB). This catalyst demonstrated improved oxygen reduction and oxygen evolution capabilities. The HELAB containing this catalyst showed a higher discharge voltage and stable charge voltage, resulting in a 34% reduction in overall over-potential compared to that without the Co3O4/GR composite. The use of saturated LiOH in 11.6 M...

INTRODUCTION EXPERIMENTAL PROCEDURE Starting materials 44 Preparation of titania sol 44 ill Prepa... more INTRODUCTION EXPERIMENTAL PROCEDURE Starting materials 44 Preparation of titania sol 44 ill Preparation of titania sol-barium methoxide mixture 44 Preparation and characterization of barium titanates 45 RESULTS AND DISCUSSION 46 Influence of preparation parameters on the stability of the titania sols and titania sol-barium methoxide mixture 46 BaTisOii (1:5 compound) 49 Ba2Ti9O20 (2:9 compound) 53 CONCLUSION 59 REFERENCES CITED 60 PAPER IL CHARACTERIZATION OF THE GROWTH OF SOL-GEL DERIVED Ba-Ti-O THIN FILMS BY LASER RAMAN SPECTROSCOPY 63 ABSTRACT INTRODUCTION EXPERIMENTAL DETAILS Thin film preparation In situ Raman cell Characterization of thin film 71 RESULTS 75 DISCUSSION 85 iv Enhancement mechanism for Raman signal 85 Variation of the intensity of Raman spectrum during in situ measurement CONCLUSION REFERENCES CITED PAPER III. PREPARATION AND CHARACTERIZATION OF SOL-GEL DERIVED Ba2Ti9O20 AND BaTisOn THIN FILMS 92

Nano Energy, 2019

A novel coral-like perovskite nanostructured layer was grown on a compact perovskite foundation l... more A novel coral-like perovskite nanostructured layer was grown on a compact perovskite foundation layer by the facile surface modification with dimethylformamide/isopropanol (DMF/IPA) as co-solvent. Surface morphological characterizations with SEM and XRD analyses revealed a growing mechanism of the new morphology, which was composed of the perovskite decomposition and recrystallization, excessive-PbI 2 extraction, and sequential formation of coral-like nanostructured perovskite layer. The coral-like perovskite nanostructures resulted in significant light scattering, enhancing the light-harvesting efficiency, and thus augmenting the photocurrent density. Moreover, the geometric configuration of the perovksite solar cells was changed from planar to bulk heterojunction, which results in the acceleration of charge separation and extraction due to the high surface area at the interface between the obtained perovskite and hole-transport layers. The optimal perovskite solar cell exhibited an impressive power conversion efficiency (PCE) of 19.47%, as compared to that of the pristine cell (17.19%).

Thin Solid Films, 2009

Cuprous oxide (Cu 2 O) and cupric oxide (CuO) thin films were deposited on glass substrates at di... more Cuprous oxide (Cu 2 O) and cupric oxide (CuO) thin films were deposited on glass substrates at different oxygen partial pressures by direct-current reactive magnetron sputtering of pure copper target in a mixture of argon and oxygen gases. Oxygen partial pressure was found to be a crucial parameter in controlling the phases and, thus, the physical properties of the deposited copper oxide thin films. Single-phase Cu 2 O thin films with cubic structure were obtained at low oxygen partial pressure between 0.147 Pa and 0.200 Pa while higher oxygen partial pressure promoted the formation of CuO thin films with base-centered monoclinic structure. Polycrystalline Cu 2 O thin films deposited with oxygen partial pressure at 0.147 Pa possessed the lowest p-type resistivity of 1.76 Ω cm as well as an optical band gap of 2.01 eV. On the other hand, polycrystalline CuO thin films deposited with oxygen partial pressure at 0.320 Pa were also single phase but showed a n-type resistivity of 0.19 Ω cm along with an optical band gap of 1.58 eV.

Procedia Technology, 2017

Amorphous indium gallium zinc oxide (a-IGZO) thin film transistor (TFT) biosensors were fabricate... more Amorphous indium gallium zinc oxide (a-IGZO) thin film transistor (TFT) biosensors were fabricated by surface modification of the a-IGZO TFT devices and the immobilization of Creatine Kinase (CK-MM) antibodies on the a-IGZO TFT devices. When the fabricated CK-MM a-IGZO TFT biosensors were used to detect CK-MM in the sample, both the field effect mobility and the Ion/Ioff ratio of the a-IGZO TFT devices were found to increase. These results indicate the potential applications for the developed a-IGZO TFT devices in biosensing.

Energy, 2017

The objectives of this work are to prepare and characterize poly[2,2 0-m-(phenylene)-5,5 0-bibenz... more The objectives of this work are to prepare and characterize poly[2,2 0-m-(phenylene)-5,5 0-bibenzimidazole]/graphene oxide (PBI/GO) solid electrolyte for direct alcohol alkaline fuel cell (DAAFC) applications. GO nanosheets are coated onto a PBI surface using a spin coater to construct the PBI/GO composite membrane. The PBI/GO composite membrane exhibits an ionic conductivity of 2.53 Â 10 À2 S cm À1 at 80 C, which is improved by 72e93% when compared with the pure PBI membrane. In addition, the methanol permeability is reduced by 18e25% by incorporating GO onto the PBI top surface. The peak power density (P max) of the PBI/GO electrolyte reaches 200 mW cm À2 when using alkaline methanol as fuel with Pt-based catalysts, or 120 mW cm À2 when fed with an ethanol and alkaline solution mixture at 80 C. Replacing the Pt-based catalysts with Hypermec™ catalysts resulted in P max of 40 and 100 mW cm À2 , for methanol and ethanol fuel cells, respectively. These superior DAAFC power outputs are ascribed to the improved anion conduction of the KOH doped GO and the suppressed methanol cross-over from high aspect ratio GO as the alcohol barrier layer.

Materials Chemistry and Physics, 2015

Abstract Indium gallium zinc oxide (InGaZnO 4 , IGZO) has attracted explosive growth in investiga... more Abstract Indium gallium zinc oxide (InGaZnO 4 , IGZO) has attracted explosive growth in investigations over the last decades as an important material in the thin-film transistor. In this study, the various nitrate precursors, including indium nitrate, gallium nitrate, and zinc nitrate, were prepared from the various metals dissolved in nitric acid. Then, we used these nitrate precursors to synthesize the IGZO precursor powder by the multistep co-precipitation method. The synthesis parameters of the co-precipitation method, such as reaction temperature, pH value and reaction time, were controlled precisely to prepare the high quality IGZO precursor powder. Finally, IGZO precursor powder was calcined at 900 °C. Then, the microstructure, the crystalline structure, the particle size distribution and specific surface area of calcined IGZO precursor powder were characterized by electron transmission microscopy, X-ray diffraction technique, dynamic light scattering method and the surface area and porosimetry analyzer, respectively. The relative density of IGZO tablet sintered at 1200 °C for 12 h is as high as 97.30%, and it showed highly InGaZnO 4 crystalline structure and the large grain size. The IGZO nanoparticles developed in our study has the potential for the high quality target materials used in the application of electronic devices.

2010 3rd International Nanoelectronics Conference (INEC), 2010

Abstract This paper presents the preparation of piezoelectric lead zirconium titanate (PZT) thick... more Abstract This paper presents the preparation of piezoelectric lead zirconium titanate (PZT) thick films and the fabrication of PZT surface acoustic waves (SAW) devices with sub-micron IDT electrodes by the micro-powder-sol-gel method. The utilization of these PZT SAW ...

2010 3rd International Nanoelectronics Conference (INEC), 2010

Abstract This paper presents the synthesis of antimony-doped tin oxide (ATO) nanorods by calcinin... more Abstract This paper presents the synthesis of antimony-doped tin oxide (ATO) nanorods by calcining coprecipitated precursors at high temperature with sodium silicate and sodium chloride additives. From the experimental results, it is found that in order to produce ...

Thin Solid Films, 1992

The isothermal growth kinetics of sol-gel derived BaTi,O,, thin films has been studied by laser R... more The isothermal growth kinetics of sol-gel derived BaTi,O,, thin films has been studied by laser Raman spectroscopy. Thin films of the precursors were spin coated on silicon wafers with platinum or gold overlayers. The films were then annealed isothermally, and Raman spectra were recorded in situ. The time-dependent intensity changes of the Raman bands could be analyzed in terms of Avrami models. The interaction of the BaTi,O,, film with the platinum or gold overlayers during heat treatment apparently increased the Raman intensity by a factor of about 100.

2008 2nd IEEE International Nanoelectronics Conference, 2008

Nano-sized powders of transparent conductive aluminum-doped zinc oxide (AZO) have been successful... more Nano-sized powders of transparent conductive aluminum-doped zinc oxide (AZO) have been successfully prepared by electrolysis-modified co-precipitation method. By adding ammonium hydroxide into the precursor solution prepared by electrolytic dissolution of zinc metal in a buffered electrolyte solution of nitric acid and ammonium nitrate with adequate addition of aluminum nitrate, co-precipitate precursors of AZO with particle size between 30 to 60

2008 2nd IEEE International Nanoelectronics Conference, 2008

Nano-powders of p-type transparent conductive copper aluminum oxide (CAO) have been successfully ... more Nano-powders of p-type transparent conductive copper aluminum oxide (CAO) have been successfully synthesized by co-precipitation method. By adding sodium hydroxide into the mixed solution of copper chloride and aluminum chloride, co-precipitate precursors of CAO with particle size around 50-60 nm were produced. After washing, filtering, and drying of the co-precipitates, nano-powders of CuAlO 2 were produced when the dried co-precipitate precursors were calcined at temperature above 1100 ℃. By aging at pH=3.5 for six hours and co-precipitating at pH=8.0, the atomic ratio of Cu/Al of the nano-powders can be maintained throughout the synthesis. After calcining at 1200℃ in air for 4 hours, the CAO co-precipitate precursors totally transformed into nano-powders of CuAlO 2 with crystal size around 64 nm. Continued calcining at 1200℃ above 4 hours led to the decomposition of CuAlO 2 into nano-powders of CuAl 2 O 4 and volatile CuO with no significant change in crystal size. Finally, it was found that by calcining under inert atmosphere, the decomposition of CuAlO 2 could be suppressed at the expense of decreasing its crystallinity. I.

Nano/Micro Engineered and Molecular Systems, 2009

In this paper, we studied a method to reduce the compressive strain in the InGaN/GaN multiple qua... more In this paper, we studied a method to reduce the compressive strain in the InGaN/GaN multiple quantum well (MQW) structures by inserting a strain relief layer between n-GaN and MQWs. The improvements in the interface quality and the optical properties were investigated by photoluminescence (PL) and high-resolution X-ray diffraction (HRXRD) analysis. The samples showed S-shaped emission energy peak and stronger

Vacuum, 2008

Transparent conducting ITO thin film has been widely used as anode material in OLEDs due to its g... more Transparent conducting ITO thin film has been widely used as anode material in OLEDs due to its good optical transparency, low electrical resistivity, ease of patterning, high work function and efficient hole injection properties. The interface between ITO and organic layer in OLED device is thus important and can influence the electrical and luminescent properties. In this report, ITO substrates were treated with 20% H 3 PO 4 solution. The corresponding changes in crystalline morphology were studied by X-ray diffraction. X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) were performed at w10 À9 Torr to study the work function and the valence band structure of ITO substrates. It was found that work function became slightly lower after the treatment, probably caused by the formation of metal complex compounds and metal hydroxides. The binding energy of In 3d 5/2 shifted from 444.6 to 445.3 eV. This shifting was referred to the formation of In-OH bonding. It would be easier to provide electron by In-OH bonding than by In-O-In or Sn-O-Sn when photons reached ITO surface. The interface between ITO and CuPc was improved through polar surface and less aggregation. In addition, the OLED devices exhibited improved performance in both external quantum efficiency and luminescence efficiency.

Surface and Coatings Technology, 2013

Abstract Gallium-doped magnesium zinc oxide (GMZO) thin films were deposited onto glass substrate... more Abstract Gallium-doped magnesium zinc oxide (GMZO) thin films were deposited onto glass substrates using RF magnetron sputtering using GMZO ceramic targets under different sputtering conditions. The substrate temperature and deposition pressure effects on the structural, electrical and optical properties of the GMZO thin film were investigated. Transparent conductive GMZO thin films were demonstrated in this study to possess a wurtzite structure, average transmittance above 80% in the 400 nm and 800 nm wavelength range with a low resistivity of 1.62 × 10 − 3 Ω cm when deposited onto glass substrates using RF magnetron sputtering.

Surface and Coatings Technology, 2013

Indium tin oxide (ITO) thin films were fabricated by spin-coating the coating solutions containin... more Indium tin oxide (ITO) thin films were fabricated by spin-coating the coating solutions containing solvothermally synthesized ITO nanoparticles on glass substrates with subsequent low temperature curing. Characterizations of the solvothermally synthesized nanoparticles confirmed that crystalline nano-sized ITO nanoparticles with crystal grain size between 17 and 20 nm were successfully obtained by solvothermal treatment of the precursor coprecipitates. By dispersing the solvothermally synthesized ITO nanoparticles in methanol, coating solutions containing well dispersed ITO nanoparticles for subsequent ITO thin film coating were prepared. It was demonstrated that the thin films fabricated by spin-coating the ITO nanoparticle coating solutions on glass substrates followed by 413.15 K heat curing under nitrogen atmosphere for 30 min were transparent conductive ITO thin films with a sheet resistance of 1.9 × 10 5 Ω/□.

Physica B: Condensed Matter, 2009

Abstract p-Type aluminum–nitrogen (Al–N) co-doped zinc oxide (ZnO) thin films were deposited on g... more Abstract p-Type aluminum–nitrogen (Al–N) co-doped zinc oxide (ZnO) thin films were deposited on glass substrate at 300 °C by RF reactive magnetron sputtering using an aluminum-doped zinc oxide (2.4 wt%Al2O3) target and N2 reactive gas. In addition, the effect of N2 reactive gas on the electrical and structural properties of Al–N co-doped ZnO thin films was also investigated. It was found that p-type Al–N co-doped ZnO thin films could be obtained only when the volume ratio of N2 in the N2-containing Ar working gas exceeded 10%. p-Type Al–N co-doped ZnO thin films with a minimum resistivity of 0.141 Ω cm, a p-type carrier concentration of 5.84×1018 cm−3, and a Hall mobility of 3.68 cm2/V s were obtained in this study when the volume ratio of N2 in the working gas was 30%.