Jyh-Ming Wu - Academia.edu (original) (raw)
Papers by Jyh-Ming Wu
Nano Energy, 2016
A contact electrification field-effect transistor (CE-FET) is first made from poly(ethylene oxide... more A contact electrification field-effect transistor (CE-FET) is first made from poly(ethylene oxide)/InSb/PET (polyethylene terephthalate) on the flexible force-pad application. The CE-FET operates on a unique principle that relies on the triboelectric potential difference that is established between the two tribosurfaces, to induce an inner electrical signal by utilizing the external frictional force. Such a signal is able to modulate the carrier transport characteristics in the FET and is self-generated to have the same effect as applying a gate signal. The traditional gate electrode in the FET is replaced by an individually mobile aluminum and a polytetrafluoroethene (PTFE) electrode to serve as a positive and negative gate voltage, respectively. The n-type rich indium (In) InSb thin film is then used as a conduction channel in the CE-FET. When the PTFE film acted as a mobile gate electrode to progressively contact the PEO surface, the drain current was increased from 6 to 12 μA by increasing the distance (d) between the PEO and the PTFE surfaces in the range from 0 to 80 μm. In contrast, when the Al film was used as a mobile electrode to gradually contact the PEO surface, the corresponding drain current decreases from 7 μA to 1.5 μA, while increasing the corresponding distance from 0 to 80 μm, respectively. Thus, the characteristic of the CE-FET has established an enhancement and depletion mode in the InSb conduction channel when the mobile electrodes of the PTFE and aluminum films were mechanically attached to the PEO surface, respectively. The CE-FET InSb is highly reliable and sensitive, which thereby opens up a new research field on the applications of the force pads.
Nanoscale research letters, Jan 18, 2013
Single-crystal indium antimony (InSb) nanowire was fabricated into middle-infrared photodetectors... more Single-crystal indium antimony (InSb) nanowire was fabricated into middle-infrared photodetectors based on a metal-semiconductor-metal (M-S-M) structure. The InSb nanowires were synthesized using an electrochemical method at room temperature. The characteristics of the FET reveal an electron concentration of 3.6 × 1017 cm-3 and an electron mobility of 215.25 cm2 V-1 s-1. The photodetectors exhibit good photoconductive performance, excellent stability, reproducibility, superior responsivity (8.4 × 104 A W-1), and quantum efficiency (1.96 × 106%). These superior properties are attributed to the high surface-to-volume ratio and single-crystal 1D nanostructure of photodetectors that significantly reduce the scattering, trapping, and the transit time between the electrodes during the transport process. Furthermore, the M-S-M structure can effectively enhance space charge effect by the formation of the Schottky contacts, which significantly assists with the electron injection and photocur...
RSC Advances, 2013
We demonstrated a flexible self-powered system that consists of a strain sensor and a nanogenerat... more We demonstrated a flexible self-powered system that consists of a strain sensor and a nanogenerator. An individual ZnSnO 3 microbelt was bonded at its ends to a polyethylene terephthalate (PET) substrate to fabricate a strain sensor and a single-nanobelt nanogenerator. The sensor and nanogenerator were connected in series and packaged by a polydimethylsiloxane (PDMS) layer. The ZnSnO 3 belongs to a R3C point group that exhibited a large piezopotential along the z-axis, so that it can be either a power source or a sensor. The piezopotential can drive electrons to flow in the circuit and serve as a power source. The piezopotential can also tune the Schottky barrier height (SBH) at the contact by varying the tensile and compressive strain owing to the piezotronic effect, so that it can serve as a strain sensor. The output current decreased as compressive strain increased, but the current increased as tensile strain increased. The sensor can be switched by bending the flexible substrate, which can act as a highly effective reversible electromechanical switcher.
Thin Solid Films, 2008
Al:ZnO nanoscrew clusters were prepared by thermal evaporation at a synthesizing temperature of 5... more Al:ZnO nanoscrew clusters were prepared by thermal evaporation at a synthesizing temperature of 500°C. The morphology and structure of the as-synthesized nanostructures were characterized by field emission scanning electron microscopy, X-ray diffraction and transmission electron microscopy, indicating that the Al:ZnO nanostructures have a single crystalline hexagonal wurtzite structure. The proposed growth mechanism involves the formation of Al:ZnO nanoscrew clusters in a heterogeneous nucleation process. The optical properties measured by cathodoluminescence, showed that the Al:ZnO nanoscrew clusters exhibit luminescence at three wavelengths −380 nm (UV emission), 490 nm (green emission) and 764 nm (near-IR emission).
The Journal of Physical Chemistry C, 2011
In ambient air, zinc acetylacetonate hydrate precursor was directly decomposed to fabricate large... more In ambient air, zinc acetylacetonate hydrate precursor was directly decomposed to fabricate large-area ZnO nanowires on a substrate using ultraviolet-light-(λ = 350−380 nm, I = 76 mW cm −2 ) assisted thermal decomposition processes at 200 °C. The growing process ...
Nanoscale, 2011
Figure S1 As-synthesized ZnO nanowires by UV-light decomposition process for (a) 3 minutes, (b) 5... more Figure S1 As-synthesized ZnO nanowires by UV-light decomposition process for (a) 3 minutes, (b) 5 minutes, (c) 10 minutes, (d) 40 minutes.
Journal of Physics D: Applied Physics, 2009
Nanocables have been formed with Sb-doped SnO2 (SnO2 : Sb) cores and SiO2 shells. First, SnO2 : S... more Nanocables have been formed with Sb-doped SnO2 (SnO2 : Sb) cores and SiO2 shells. First, SnO2 : Sb nanowires were synthesized by a vapour-liquid-solid process at 900 °C. Subsequently, thin SiO2 shells were deposited onto the surfaces of these SnO2 : Sb nanowires. Thin-film x-ray diffraction showed that all the as-synthesized core-shell nanocables had a single-phase SnO2 rutile structure. Field
Journal of Nanoscience and Nanotechnology, 2010
High density Sb-doped SnO 2 nanobelts and beak-like nanorods were synthesized on alumina substrat... more High density Sb-doped SnO 2 nanobelts and beak-like nanorods were synthesized on alumina substrates using thermal evaporation. X-ray diffraction (XRD) pattern shows that both the nanobelts and beak-like nanorods are single crystals with the tetragonal rutile structure. Transmission electron microscopy (TEM) images show that the nanobelts grow along the [110] direction, but the nanorods grow with an abrupt change from the [101] direction to the [301] direction. X-ray photoelectron spectroscopy (XPS) analysis shows that the Sb 3d 3/2 peak of not fully oxidized beak-like nanorods shifts from 540.5 eV to 535.4 eV, and the Sn 3d 3/2 peak also shifts from 496.3 eV to 492.8 eV. Room temperature cathodoluminescence (CL) measurements show that both the nanobelts and beak-like nanorods exhibit blue and orange emissions that are related to the interstitial defects and oxygen deficiencies. The comparative study of CL measurements between nanobelts and beak-like nanorods demonstrate that the optical properties can be modified by altering the oxygen deficiencies.
Journal of The Electrochemical Society, 2007
ABSTRACT Rutile TiO2 nanowires and colloidal anatase paste (film-type) were synthesized on a sili... more ABSTRACT Rutile TiO2 nanowires and colloidal anatase paste (film-type) were synthesized on a silicon (Si) substrate by the thermal evaporation and sol-gel process, respectively. Field-emission scanning electron microscopy images showed nanowires with diameters of 60 - 90 nm and similar to 3 - 4 mu m in length. The morphology of the anatase paste was mesoporous, and the size of the nanoparticles was 20 - 40 nm in diameter. High-resolution transmission electron microscopy demonstrated that the rutile nanowires and anatase nanoparticles were single crystalline. Comparison of their photocatalytic properties revealed that the rutile nanowires had high specific surface area, were well-crystallized, and possessed photocatalytic activities as high as those of the mesoporous anatase paste. (c) 2007 The Electrochemical Society
Diamond and Related Materials, 2009
Diamond and Related Materials, 2010
... The elemental composition change and relevant chemical bonding of the SWCNT film during the p... more ... The elemental composition change and relevant chemical bonding of the SWCNT film during the plasma treatments were investigated by X-ray photoelectron spectroscopy (XPS, ULVAC-PHI PHI Quantera SXM) with a hemispherical capacitor analyzer. ...
ACS Applied Materials & Interfaces, 2014
The ultrafine ZnO nanoparticles/nanowires were successfully synthesized on a flexible and transpa... more The ultrafine ZnO nanoparticles/nanowires were successfully synthesized on a flexible and transparent substrate by an ultraviolet-light decomposition process. We demonstrate that water molecules can affect the morphology of ZnO nanostructures. An ultraviolet lamp (λ ~ 380 nm, 75 mW cm(-2)) can be used to irradiate Zn(AcAc)2 and Zn(AcAc)2·H2O precursors, which rapidly synthesize ZnO nanoparticles and nanowires, respectively. High-resolution transmission electron microscopy (HRTEM) images and a selected-area electron diffraction pattern revealed that the single-crystal nanoparticles were comprised of wurtzite structure ZnO. The nanowires consisted of ultrafine nanoparticles. On the basis of the Debye-Scherrer formula, the particle size of ZnO was calculated as ~6-9 nm. The more water molecules the precursor had, the more OH(-) and Zn[(OH)4](2-) it put out. Moreover, due to the Zn[(OH)4](2-) and Zn(OH)2 species formed on the surface of the ZnO nanocrystals, they facilitated the one-dimensional nanowires during the crystal growth process. On the basis of our investigations, oxygen vacancies, hydroxyl, and zinc hydroxide all acted as key components in the formation processes that determined photoresponsive properties.
Journal of Crystal Growth, 2005
Japanese Journal of Applied Physics, 2008
Abstract Single crystalline tetragonal rutile SnO 2 nanorods with curved beak-like tips of variou... more Abstract Single crystalline tetragonal rutile SnO 2 nanorods with curved beak-like tips of various lengths were synthesized using Au as a catalyst by thermal evaporation with different precursor flow rates. The cathodoluminescence (CL) spectrum shows that the ...
ACS Nano, 2012
We demonstrated the first application of a pyroelectric nanogenerator as a self-powered sensor (o... more We demonstrated the first application of a pyroelectric nanogenerator as a self-powered sensor (or active sensor) for detecting a change in temperature. The device consists of a single lead zirconate titanate (PZT) micro/nanowire that is placed on a thin glass substrate and bonded at its two ends, and it is packaged by polydimethylsiloxane (PDMS). By using the device to touch a heat source, the output voltage linearly increases with an increasing rate of change in temperature. The response time and reset time of the fabricated sensor are about 0.9 and 3 s, respectively. The minimum detecting limit of the change in temperature is about 0.4 K at room temperature. The sensor can be used to detect the temperature of a finger tip. The electricity generated under a large change in temperature can light up a liquid crystal display (LCD).
Nano Energy, 2016
A contact electrification field-effect transistor (CE-FET) is first made from poly(ethylene oxide... more A contact electrification field-effect transistor (CE-FET) is first made from poly(ethylene oxide)/InSb/PET (polyethylene terephthalate) on the flexible force-pad application. The CE-FET operates on a unique principle that relies on the triboelectric potential difference that is established between the two tribosurfaces, to induce an inner electrical signal by utilizing the external frictional force. Such a signal is able to modulate the carrier transport characteristics in the FET and is self-generated to have the same effect as applying a gate signal. The traditional gate electrode in the FET is replaced by an individually mobile aluminum and a polytetrafluoroethene (PTFE) electrode to serve as a positive and negative gate voltage, respectively. The n-type rich indium (In) InSb thin film is then used as a conduction channel in the CE-FET. When the PTFE film acted as a mobile gate electrode to progressively contact the PEO surface, the drain current was increased from 6 to 12 μA by increasing the distance (d) between the PEO and the PTFE surfaces in the range from 0 to 80 μm. In contrast, when the Al film was used as a mobile electrode to gradually contact the PEO surface, the corresponding drain current decreases from 7 μA to 1.5 μA, while increasing the corresponding distance from 0 to 80 μm, respectively. Thus, the characteristic of the CE-FET has established an enhancement and depletion mode in the InSb conduction channel when the mobile electrodes of the PTFE and aluminum films were mechanically attached to the PEO surface, respectively. The CE-FET InSb is highly reliable and sensitive, which thereby opens up a new research field on the applications of the force pads.
Nanoscale research letters, Jan 18, 2013
Single-crystal indium antimony (InSb) nanowire was fabricated into middle-infrared photodetectors... more Single-crystal indium antimony (InSb) nanowire was fabricated into middle-infrared photodetectors based on a metal-semiconductor-metal (M-S-M) structure. The InSb nanowires were synthesized using an electrochemical method at room temperature. The characteristics of the FET reveal an electron concentration of 3.6 × 1017 cm-3 and an electron mobility of 215.25 cm2 V-1 s-1. The photodetectors exhibit good photoconductive performance, excellent stability, reproducibility, superior responsivity (8.4 × 104 A W-1), and quantum efficiency (1.96 × 106%). These superior properties are attributed to the high surface-to-volume ratio and single-crystal 1D nanostructure of photodetectors that significantly reduce the scattering, trapping, and the transit time between the electrodes during the transport process. Furthermore, the M-S-M structure can effectively enhance space charge effect by the formation of the Schottky contacts, which significantly assists with the electron injection and photocur...
RSC Advances, 2013
We demonstrated a flexible self-powered system that consists of a strain sensor and a nanogenerat... more We demonstrated a flexible self-powered system that consists of a strain sensor and a nanogenerator. An individual ZnSnO 3 microbelt was bonded at its ends to a polyethylene terephthalate (PET) substrate to fabricate a strain sensor and a single-nanobelt nanogenerator. The sensor and nanogenerator were connected in series and packaged by a polydimethylsiloxane (PDMS) layer. The ZnSnO 3 belongs to a R3C point group that exhibited a large piezopotential along the z-axis, so that it can be either a power source or a sensor. The piezopotential can drive electrons to flow in the circuit and serve as a power source. The piezopotential can also tune the Schottky barrier height (SBH) at the contact by varying the tensile and compressive strain owing to the piezotronic effect, so that it can serve as a strain sensor. The output current decreased as compressive strain increased, but the current increased as tensile strain increased. The sensor can be switched by bending the flexible substrate, which can act as a highly effective reversible electromechanical switcher.
Thin Solid Films, 2008
Al:ZnO nanoscrew clusters were prepared by thermal evaporation at a synthesizing temperature of 5... more Al:ZnO nanoscrew clusters were prepared by thermal evaporation at a synthesizing temperature of 500°C. The morphology and structure of the as-synthesized nanostructures were characterized by field emission scanning electron microscopy, X-ray diffraction and transmission electron microscopy, indicating that the Al:ZnO nanostructures have a single crystalline hexagonal wurtzite structure. The proposed growth mechanism involves the formation of Al:ZnO nanoscrew clusters in a heterogeneous nucleation process. The optical properties measured by cathodoluminescence, showed that the Al:ZnO nanoscrew clusters exhibit luminescence at three wavelengths −380 nm (UV emission), 490 nm (green emission) and 764 nm (near-IR emission).
The Journal of Physical Chemistry C, 2011
In ambient air, zinc acetylacetonate hydrate precursor was directly decomposed to fabricate large... more In ambient air, zinc acetylacetonate hydrate precursor was directly decomposed to fabricate large-area ZnO nanowires on a substrate using ultraviolet-light-(λ = 350−380 nm, I = 76 mW cm −2 ) assisted thermal decomposition processes at 200 °C. The growing process ...
Nanoscale, 2011
Figure S1 As-synthesized ZnO nanowires by UV-light decomposition process for (a) 3 minutes, (b) 5... more Figure S1 As-synthesized ZnO nanowires by UV-light decomposition process for (a) 3 minutes, (b) 5 minutes, (c) 10 minutes, (d) 40 minutes.
Journal of Physics D: Applied Physics, 2009
Nanocables have been formed with Sb-doped SnO2 (SnO2 : Sb) cores and SiO2 shells. First, SnO2 : S... more Nanocables have been formed with Sb-doped SnO2 (SnO2 : Sb) cores and SiO2 shells. First, SnO2 : Sb nanowires were synthesized by a vapour-liquid-solid process at 900 °C. Subsequently, thin SiO2 shells were deposited onto the surfaces of these SnO2 : Sb nanowires. Thin-film x-ray diffraction showed that all the as-synthesized core-shell nanocables had a single-phase SnO2 rutile structure. Field
Journal of Nanoscience and Nanotechnology, 2010
High density Sb-doped SnO 2 nanobelts and beak-like nanorods were synthesized on alumina substrat... more High density Sb-doped SnO 2 nanobelts and beak-like nanorods were synthesized on alumina substrates using thermal evaporation. X-ray diffraction (XRD) pattern shows that both the nanobelts and beak-like nanorods are single crystals with the tetragonal rutile structure. Transmission electron microscopy (TEM) images show that the nanobelts grow along the [110] direction, but the nanorods grow with an abrupt change from the [101] direction to the [301] direction. X-ray photoelectron spectroscopy (XPS) analysis shows that the Sb 3d 3/2 peak of not fully oxidized beak-like nanorods shifts from 540.5 eV to 535.4 eV, and the Sn 3d 3/2 peak also shifts from 496.3 eV to 492.8 eV. Room temperature cathodoluminescence (CL) measurements show that both the nanobelts and beak-like nanorods exhibit blue and orange emissions that are related to the interstitial defects and oxygen deficiencies. The comparative study of CL measurements between nanobelts and beak-like nanorods demonstrate that the optical properties can be modified by altering the oxygen deficiencies.
Journal of The Electrochemical Society, 2007
ABSTRACT Rutile TiO2 nanowires and colloidal anatase paste (film-type) were synthesized on a sili... more ABSTRACT Rutile TiO2 nanowires and colloidal anatase paste (film-type) were synthesized on a silicon (Si) substrate by the thermal evaporation and sol-gel process, respectively. Field-emission scanning electron microscopy images showed nanowires with diameters of 60 - 90 nm and similar to 3 - 4 mu m in length. The morphology of the anatase paste was mesoporous, and the size of the nanoparticles was 20 - 40 nm in diameter. High-resolution transmission electron microscopy demonstrated that the rutile nanowires and anatase nanoparticles were single crystalline. Comparison of their photocatalytic properties revealed that the rutile nanowires had high specific surface area, were well-crystallized, and possessed photocatalytic activities as high as those of the mesoporous anatase paste. (c) 2007 The Electrochemical Society
Diamond and Related Materials, 2009
Diamond and Related Materials, 2010
... The elemental composition change and relevant chemical bonding of the SWCNT film during the p... more ... The elemental composition change and relevant chemical bonding of the SWCNT film during the plasma treatments were investigated by X-ray photoelectron spectroscopy (XPS, ULVAC-PHI PHI Quantera SXM) with a hemispherical capacitor analyzer. ...
ACS Applied Materials & Interfaces, 2014
The ultrafine ZnO nanoparticles/nanowires were successfully synthesized on a flexible and transpa... more The ultrafine ZnO nanoparticles/nanowires were successfully synthesized on a flexible and transparent substrate by an ultraviolet-light decomposition process. We demonstrate that water molecules can affect the morphology of ZnO nanostructures. An ultraviolet lamp (λ ~ 380 nm, 75 mW cm(-2)) can be used to irradiate Zn(AcAc)2 and Zn(AcAc)2·H2O precursors, which rapidly synthesize ZnO nanoparticles and nanowires, respectively. High-resolution transmission electron microscopy (HRTEM) images and a selected-area electron diffraction pattern revealed that the single-crystal nanoparticles were comprised of wurtzite structure ZnO. The nanowires consisted of ultrafine nanoparticles. On the basis of the Debye-Scherrer formula, the particle size of ZnO was calculated as ~6-9 nm. The more water molecules the precursor had, the more OH(-) and Zn[(OH)4](2-) it put out. Moreover, due to the Zn[(OH)4](2-) and Zn(OH)2 species formed on the surface of the ZnO nanocrystals, they facilitated the one-dimensional nanowires during the crystal growth process. On the basis of our investigations, oxygen vacancies, hydroxyl, and zinc hydroxide all acted as key components in the formation processes that determined photoresponsive properties.
Journal of Crystal Growth, 2005
Japanese Journal of Applied Physics, 2008
Abstract Single crystalline tetragonal rutile SnO 2 nanorods with curved beak-like tips of variou... more Abstract Single crystalline tetragonal rutile SnO 2 nanorods with curved beak-like tips of various lengths were synthesized using Au as a catalyst by thermal evaporation with different precursor flow rates. The cathodoluminescence (CL) spectrum shows that the ...
ACS Nano, 2012
We demonstrated the first application of a pyroelectric nanogenerator as a self-powered sensor (o... more We demonstrated the first application of a pyroelectric nanogenerator as a self-powered sensor (or active sensor) for detecting a change in temperature. The device consists of a single lead zirconate titanate (PZT) micro/nanowire that is placed on a thin glass substrate and bonded at its two ends, and it is packaged by polydimethylsiloxane (PDMS). By using the device to touch a heat source, the output voltage linearly increases with an increasing rate of change in temperature. The response time and reset time of the fabricated sensor are about 0.9 and 3 s, respectively. The minimum detecting limit of the change in temperature is about 0.4 K at room temperature. The sensor can be used to detect the temperature of a finger tip. The electricity generated under a large change in temperature can light up a liquid crystal display (LCD).