The Ni, Fe, Co and Cu single and multilayer nanowire arrays to make perpendicular magnetic recording media were fabricated with nanoporous anodic aluminum oxide (AAO) templates from Watt solution and additives by the ...The Ni, Fe, Co and Cu single and multilayer nanowire arrays to make perpendicular magnetic recording media were fabricated with nanoporous anodic aluminum oxide (AAO) templates from Watt solution and additives by the DC electrodeposition. The results show that the diameters of Ni, Fe, Co and Cu single and multilayer nanowires in AAO templates are 40-80 nm and the lengths are about 30 μm with the aspect ratio of 350-750. The magnetic properties of the prepared nanowires are different under different electrodepositing conditions. The remanences (Br) of Ni/Cu/Fe multilayer nanowires are lower than those of others multilayer nanowires, and coercivity (Hc) of Ni/Cu/Fe multilayer nanowires are lower than those of others multilayer nanowires. These are compatible with the required conditions of high density magnetic media devices that should have the low coercivity to easily success magnetization and high remanence to keep magnetization after removal of magnetic field.展开更多
The synthesis of Pd-Ag alloy nanowires in nanopores of porous anodic aluminum oxide (AAO) template by electrochemical deposition technique was reported. Pd-Ag alloy nanowires with 16%-25% Ag content are expected to ...The synthesis of Pd-Ag alloy nanowires in nanopores of porous anodic aluminum oxide (AAO) template by electrochemical deposition technique was reported. Pd-Ag alloy nanowires with 16%-25% Ag content are expected to serve as candidates of useful nanomaterials for the hydrogen sensors. Scanning electron microscopy (SEM) and energy dispersed X-ray spectroscopy (EDX) were employed to characterize the morphologies and compositions of the Pd-Ag nanowires. X-ray diffraction (XRD) was used to characterize the phase properties of the Pd-Ag nanowires. Pd-Ag alloy nanowire arrays with 17.28%-23.76% Ag content have been successfully fabricated by applying potentials ranging from -0.8 to -1.0 V (vs SCE). The sizes of the alloy nanowires are in agreement with the diameter of AAO nanopores. The underpotential deposition of Ag+ on Pd and Au plays an important role in producing an exceptionally high Ag content in the alloy. Alloy compositions can still be controlled by adjusting the ion concentration ratio of Pd^2+ and Ag+ and the electrodeposition processes. XRD shows that nanowires obtained are in the form of alloy of Pd and Ag.展开更多
Ni nanowires were prepared by electrodeposition in porous anodized aluminum oxide (AAO) template from a composite electrolyte solution. Well-ordered Ni nanowire arrays with controllable length were then made by the ...Ni nanowires were prepared by electrodeposition in porous anodized aluminum oxide (AAO) template from a composite electrolyte solution. Well-ordered Ni nanowire arrays with controllable length were then made by the partial removal of AAO using a mixture of phosphoric acid and chromic acid (6 wt pct H3PO4:1.8 wt pct H3CrO4). The images of Ni nanowire arrays were studied by scanning electron microscopy (SEM) to determine the relationship between etching time and the length of Ni nanowire arrays. The results indicate that the length of nanowires exposed from the template can be accurately controlled by controlling etching time.展开更多
The well-aligned carbon nanotubes (CNTs) arrays with opened ends were prepared in ordered pores of anodic aluminum oxide (AAO) template by the chemical vapor deposition (CVD) method. After then, silicon nanowires (SiN...The well-aligned carbon nanotubes (CNTs) arrays with opened ends were prepared in ordered pores of anodic aluminum oxide (AAO) template by the chemical vapor deposition (CVD) method. After then, silicon nanowires (SiNWs) were deposited in the hollow cavities of CNTs. By using this method, CNTs/SiNWs core-sheath composite structure arrays were synthesized successfully. Growing structures and physical properties of the CNTs/SiNWs composite structure arrays were analyzed and researched by the scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction spectrum (XRD), respectively. The field emission (FE) behavior of the CNTs/SiNWs composite structure arrays was studied based on Fowler-Nordheim tunneling mechanism and current-voltage (/-V) curve. And the photoluminescence (PL) was also characterized. Significantly, the CNTs/SiNWs core-sheath composite structure nanowire fabricated by AAO template method is characteristic of a metal/semiconductor (M/S) behavior and can展开更多
One of the most unique structural characteristics of carbon nanotubes(CNTs) differentiating from other carbon materials is their hollow nanochannles,which can be utilized for encapsulating and loading foreign matters....One of the most unique structural characteristics of carbon nanotubes(CNTs) differentiating from other carbon materials is their hollow nanochannles,which can be utilized for encapsulating and loading foreign matters.The anodic aluminum oxide(AAO) template technique enables the diameter,length,and cap structure control of the replicated CNTs,and thus shows advantages in pore structure control over the traditional CNT growth approaches.This review details the synthesis of CNTs with tunable diameter,length,wall thickness,and crystalline by using the AAO template method.The doping of heteroatoms and filling of foreign matters into AAO-CNTs are also addressed.Moreover,the main challenges and developing trends of the AAO template method are discussed.展开更多
Highly ordered poly crystalline Si nanowire arrays were synthesized in porous anodic aluminum oxide (AAO) templates by the chemical vapor deposition (CVD) method. The morphological structure, the crystal character of ...Highly ordered poly crystalline Si nanowire arrays were synthesized in porous anodic aluminum oxide (AAO) templates by the chemical vapor deposition (CVD) method. The morphological structure, the crystal character of Si nanowire arrays and the individual nanowire were analyzed by the transmission electron microscopy (TEM), scanning electron microscopy (SEM), atom force microscopy (AFM) and the X-ray diffraction spectrum (XRD), respectively. It is shown that most fabricated silicon nanowires (SiNWs) tend to be assembled parallelly in bundles and constructed with highly orientated arrays. This method provides a simple and low cost fabricating craftwork and the diameters and lengths of SiNWs can be controlled, the large area Si nanowire arrays can be achieved easily under such a way. The curling and twisting SiNWs are fewer than those by other synthesis methods.展开更多
Anodic aluminum oxide(AAO) with highly ordered nanoscale pores which are monodisperse and mutually parallel can be produced through a self-organized electrochemical process.Subsequent deposition of materials into the ...Anodic aluminum oxide(AAO) with highly ordered nanoscale pores which are monodisperse and mutually parallel can be produced through a self-organized electrochemical process.Subsequent deposition of materials into the nanopores produces AAO embedded nanowire arrays.Whilst the templates can be further removed to obtain free individual nanowires,the embedded nanowires form an interesting nanocomposite structure.Recent research activities on the fabrication and characteriza-tion of AAO template based magnetic nanowires are reviewed in this article.Studies of specific systems are given as an example of the research in the area.展开更多
Carbon nanotube (CNT) arrays confined by porous anodic aluminum oxide (AAO) template were synthe- sized using ethanol as reactant carbon source at low pressure. Images by scanning electron microscope (SEM) and low mag...Carbon nanotube (CNT) arrays confined by porous anodic aluminum oxide (AAO) template were synthe- sized using ethanol as reactant carbon source at low pressure. Images by scanning electron microscope (SEM) and low magnification transmission electron microscopy (TEM) show that these CNTs have highly uniform outer diameter and length, absolutely controlled by the diameter and depth of nano-channel arrays of the AAO. High resolution transmis- sion electron microscopy (HRTEM) imaging indicates that the graphitization of the CNT walls is better than the results reported on this kind of template-based CNT arrays, al- though it is not so good as that of multiwalled carbon nano- tubes (MWCNTs) synthesized by catalysis. CNTs synthesized using acetylene as reactant gas show much less graphitiza- tion than those prepared using ethanol by comparing the results of HRTEM and Raman spectroscopy. The etching effects of decomposed OH radicals on the amorphous carbon and the roughness of AAO nano-channel arrays on the CNTs growth were employed to explain the graphitization and growth of the CNTs.展开更多
Silver nanorod arrays have been fabricated by alternat-ing current(AC) and pulsed direct current(DC) electrodeposition in porous anodic aluminum oxide(AAO) templates with controlled pore diameters of 19,38,and 6...Silver nanorod arrays have been fabricated by alternat-ing current(AC) and pulsed direct current(DC) electrodeposition in porous anodic aluminum oxide(AAO) templates with controlled pore diameters of 19,38,and 65 nm,respectively.The variation of their optical absorption properties with the incident angle and the nanorods length(corresponding to the electrodeposition time) has been investigated.Optical absorption spectra show that the posi-tion of longitudinal surface plasmon resonance(LSPR) peak has a small blueshift with the increase of incident angle of the excitation light.While the aspect ratio of the nanorods increases,the position of LSPR peak first redshifts and then blueshifts to a certain wave-length.Furthermore,the position of LSPR peak can be tuned,ranging from 550 nm to 900 nm,which makes it possible to cou-ple various wavelength of excitation source to assist radiative en-ergy transfer to the acceptor.展开更多
A novel soft polymer template containing a double-layer structure,which includes a thin layer of polymethylmethacrylate(PMMA)used as a pattern layer and a thicker layer of polydimethylsiloxane(PDMS)used as a back laye...A novel soft polymer template containing a double-layer structure,which includes a thin layer of polymethylmethacrylate(PMMA)used as a pattern layer and a thicker layer of polydimethylsiloxane(PDMS)used as a back layer,was fabricated from a replica molding process.Anodic aluminum oxide(AAO)template was used as the replica mold to be replicated to the polymethylmethacrylate layer by a thermal infiltration process under a vacuum condition.Results indicate that PMMA/PDMS soft templates with different sizes could be easily fabricated from the as-prepared AAO replica mold.The PMMA/PDMS soft templates were then employed to imprint a TiO_2 gel for achieving TiO_2 nano-pore arrays.After the imprinting process,the PDMS layer was firstly peeled off and the PMMA layer was then removed into acetonitrile,which can avoid any demolding problems like damages or distortions.The TiO_2 nano-pore arrays with the crystalline of anatase could be obtained at a heat treatment temperature of 450°C.展开更多
The highly ordered CuO nanowire arrays of composite-oxides were synthesized within a porous anodic aluminum oxide(AAO) template by a citrate-based sol-gel route. A vacuum system was applied to draw the gel into the te...The highly ordered CuO nanowire arrays of composite-oxides were synthesized within a porous anodic aluminum oxide(AAO) template by a citrate-based sol-gel route. A vacuum system was applied to draw the gel into the template pores, which conquers the only driving force of this technique—capillary action, then the gel was thermally treated to prepare desired CuO nanowires. The results of scanning electron microscopy(SEM) indicate that the CuO nanowires are very uniformly assembled and parallel to each other in the pores of the anodic aluminum oxide(AAO) template membranes. The results of X-ray diffraction(XRD) and the selected-area electron diffraction(SAED) indicate that the CuO nanowires are monoclinic-type crystalline structure. Furthermore, X-ray photoelectron spectroscopy (XPS) demonstrates that the stoichiometric CuO is formed.展开更多
Anodic aluminum oxide (AAO) membranes with large ordered pore domains were successfully prepared by adopting the anneal pre-treatment of polycrystalline alu- minum sheets. A statistical method with Gaussian distributi...Anodic aluminum oxide (AAO) membranes with large ordered pore domains were successfully prepared by adopting the anneal pre-treatment of polycrystalline alu- minum sheets. A statistical method with Gaussian distribution was introduced to quantitatively study the size of the domain with ordered pores. The largest average area of ordered pore domains was 2.6 μm2±0.11 μm2. The corresponding AAO membrane was synthesized by aluminum sheets annealed at 893 K for 24 h.展开更多
文摘The Ni, Fe, Co and Cu single and multilayer nanowire arrays to make perpendicular magnetic recording media were fabricated with nanoporous anodic aluminum oxide (AAO) templates from Watt solution and additives by the DC electrodeposition. The results show that the diameters of Ni, Fe, Co and Cu single and multilayer nanowires in AAO templates are 40-80 nm and the lengths are about 30 μm with the aspect ratio of 350-750. The magnetic properties of the prepared nanowires are different under different electrodepositing conditions. The remanences (Br) of Ni/Cu/Fe multilayer nanowires are lower than those of others multilayer nanowires, and coercivity (Hc) of Ni/Cu/Fe multilayer nanowires are lower than those of others multilayer nanowires. These are compatible with the required conditions of high density magnetic media devices that should have the low coercivity to easily success magnetization and high remanence to keep magnetization after removal of magnetic field.
基金supported by the National Natural Science Foundation of China under Grant No.20373015the Hunan Education Office under Grant No.04C033.
文摘The synthesis of Pd-Ag alloy nanowires in nanopores of porous anodic aluminum oxide (AAO) template by electrochemical deposition technique was reported. Pd-Ag alloy nanowires with 16%-25% Ag content are expected to serve as candidates of useful nanomaterials for the hydrogen sensors. Scanning electron microscopy (SEM) and energy dispersed X-ray spectroscopy (EDX) were employed to characterize the morphologies and compositions of the Pd-Ag nanowires. X-ray diffraction (XRD) was used to characterize the phase properties of the Pd-Ag nanowires. Pd-Ag alloy nanowire arrays with 17.28%-23.76% Ag content have been successfully fabricated by applying potentials ranging from -0.8 to -1.0 V (vs SCE). The sizes of the alloy nanowires are in agreement with the diameter of AAO nanopores. The underpotential deposition of Ag+ on Pd and Au plays an important role in producing an exceptionally high Ag content in the alloy. Alloy compositions can still be controlled by adjusting the ion concentration ratio of Pd^2+ and Ag+ and the electrodeposition processes. XRD shows that nanowires obtained are in the form of alloy of Pd and Ag.
基金This work was supported by the National Natural Science Foundation of China under grant No.50473012.
文摘Ni nanowires were prepared by electrodeposition in porous anodized aluminum oxide (AAO) template from a composite electrolyte solution. Well-ordered Ni nanowire arrays with controllable length were then made by the partial removal of AAO using a mixture of phosphoric acid and chromic acid (6 wt pct H3PO4:1.8 wt pct H3CrO4). The images of Ni nanowire arrays were studied by scanning electron microscopy (SEM) to determine the relationship between etching time and the length of Ni nanowire arrays. The results indicate that the length of nanowires exposed from the template can be accurately controlled by controlling etching time.
基金The authors thank Mr. Cao Guixun of Analysis and Testing Center of Gansu Province Cor usefulhelp and discussion. This work was supported by the National Natural Science Foundation of China (Grant Nos. 69890220 and 69871013).
文摘The well-aligned carbon nanotubes (CNTs) arrays with opened ends were prepared in ordered pores of anodic aluminum oxide (AAO) template by the chemical vapor deposition (CVD) method. After then, silicon nanowires (SiNWs) were deposited in the hollow cavities of CNTs. By using this method, CNTs/SiNWs core-sheath composite structure arrays were synthesized successfully. Growing structures and physical properties of the CNTs/SiNWs composite structure arrays were analyzed and researched by the scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction spectrum (XRD), respectively. The field emission (FE) behavior of the CNTs/SiNWs composite structure arrays was studied based on Fowler-Nordheim tunneling mechanism and current-voltage (/-V) curve. And the photoluminescence (PL) was also characterized. Significantly, the CNTs/SiNWs core-sheath composite structure nanowire fabricated by AAO template method is characteristic of a metal/semiconductor (M/S) behavior and can
基金supported by the Ministry of Science and Technology of China (2011CB932601,2011CB932604,and 2008DFA51400)the Clean Energy Facing the Future Program between the Chinese Academy of Sciences and British Petrleum+1 种基金National Natural Science Foundation of China (50921004 and 50872137)Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘One of the most unique structural characteristics of carbon nanotubes(CNTs) differentiating from other carbon materials is their hollow nanochannles,which can be utilized for encapsulating and loading foreign matters.The anodic aluminum oxide(AAO) template technique enables the diameter,length,and cap structure control of the replicated CNTs,and thus shows advantages in pore structure control over the traditional CNT growth approaches.This review details the synthesis of CNTs with tunable diameter,length,wall thickness,and crystalline by using the AAO template method.The doping of heteroatoms and filling of foreign matters into AAO-CNTs are also addressed.Moreover,the main challenges and developing trends of the AAO template method are discussed.
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 69890220 and 69871013).
文摘Highly ordered poly crystalline Si nanowire arrays were synthesized in porous anodic aluminum oxide (AAO) templates by the chemical vapor deposition (CVD) method. The morphological structure, the crystal character of Si nanowire arrays and the individual nanowire were analyzed by the transmission electron microscopy (TEM), scanning electron microscopy (SEM), atom force microscopy (AFM) and the X-ray diffraction spectrum (XRD), respectively. It is shown that most fabricated silicon nanowires (SiNWs) tend to be assembled parallelly in bundles and constructed with highly orientated arrays. This method provides a simple and low cost fabricating craftwork and the diameters and lengths of SiNWs can be controlled, the large area Si nanowire arrays can be achieved easily under such a way. The curling and twisting SiNWs are fewer than those by other synthesis methods.
文摘Anodic aluminum oxide(AAO) with highly ordered nanoscale pores which are monodisperse and mutually parallel can be produced through a self-organized electrochemical process.Subsequent deposition of materials into the nanopores produces AAO embedded nanowire arrays.Whilst the templates can be further removed to obtain free individual nanowires,the embedded nanowires form an interesting nanocomposite structure.Recent research activities on the fabrication and characteriza-tion of AAO template based magnetic nanowires are reviewed in this article.Studies of specific systems are given as an example of the research in the area.
基金the Key Project of Knowledge Innovation Project of the Chinese Academic of sciences.the National Natural Science Foundation of China(Grant No.10375085)the National Basic Research Program of China(Grant No.2003CB716901)Shanghai Nanometer Special Foundation(Grant No.0352nn050).
文摘Carbon nanotube (CNT) arrays confined by porous anodic aluminum oxide (AAO) template were synthe- sized using ethanol as reactant carbon source at low pressure. Images by scanning electron microscope (SEM) and low magnification transmission electron microscopy (TEM) show that these CNTs have highly uniform outer diameter and length, absolutely controlled by the diameter and depth of nano-channel arrays of the AAO. High resolution transmis- sion electron microscopy (HRTEM) imaging indicates that the graphitization of the CNT walls is better than the results reported on this kind of template-based CNT arrays, al- though it is not so good as that of multiwalled carbon nano- tubes (MWCNTs) synthesized by catalysis. CNTs synthesized using acetylene as reactant gas show much less graphitiza- tion than those prepared using ethanol by comparing the results of HRTEM and Raman spectroscopy. The etching effects of decomposed OH radicals on the amorphous carbon and the roughness of AAO nano-channel arrays on the CNTs growth were employed to explain the graphitization and growth of the CNTs.
基金Supported by the National Natural Science Foundation of China (10874134)
文摘Silver nanorod arrays have been fabricated by alternat-ing current(AC) and pulsed direct current(DC) electrodeposition in porous anodic aluminum oxide(AAO) templates with controlled pore diameters of 19,38,and 65 nm,respectively.The variation of their optical absorption properties with the incident angle and the nanorods length(corresponding to the electrodeposition time) has been investigated.Optical absorption spectra show that the posi-tion of longitudinal surface plasmon resonance(LSPR) peak has a small blueshift with the increase of incident angle of the excitation light.While the aspect ratio of the nanorods increases,the position of LSPR peak first redshifts and then blueshifts to a certain wave-length.Furthermore,the position of LSPR peak can be tuned,ranging from 550 nm to 900 nm,which makes it possible to cou-ple various wavelength of excitation source to assist radiative en-ergy transfer to the acceptor.
基金supported by the Ministry of Science and Technology of China through 863-project under grant 2009AA03Z218the Major Program of the National Natural Science Foundation of China under Grant No.90923012the Research Fund for the Doctoral Program of Higher Education of China under grant 200806980023
文摘A novel soft polymer template containing a double-layer structure,which includes a thin layer of polymethylmethacrylate(PMMA)used as a pattern layer and a thicker layer of polydimethylsiloxane(PDMS)used as a back layer,was fabricated from a replica molding process.Anodic aluminum oxide(AAO)template was used as the replica mold to be replicated to the polymethylmethacrylate layer by a thermal infiltration process under a vacuum condition.Results indicate that PMMA/PDMS soft templates with different sizes could be easily fabricated from the as-prepared AAO replica mold.The PMMA/PDMS soft templates were then employed to imprint a TiO_2 gel for achieving TiO_2 nano-pore arrays.After the imprinting process,the PDMS layer was firstly peeled off and the PMMA layer was then removed into acetonitrile,which can avoid any demolding problems like damages or distortions.The TiO_2 nano-pore arrays with the crystalline of anatase could be obtained at a heat treatment temperature of 450°C.
基金Project(200623) supported by the Science Foundation of Shenzhen University, China
文摘The highly ordered CuO nanowire arrays of composite-oxides were synthesized within a porous anodic aluminum oxide(AAO) template by a citrate-based sol-gel route. A vacuum system was applied to draw the gel into the template pores, which conquers the only driving force of this technique—capillary action, then the gel was thermally treated to prepare desired CuO nanowires. The results of scanning electron microscopy(SEM) indicate that the CuO nanowires are very uniformly assembled and parallel to each other in the pores of the anodic aluminum oxide(AAO) template membranes. The results of X-ray diffraction(XRD) and the selected-area electron diffraction(SAED) indicate that the CuO nanowires are monoclinic-type crystalline structure. Furthermore, X-ray photoelectron spectroscopy (XPS) demonstrates that the stoichiometric CuO is formed.
基金the National "973" Project of China (Gratn No. 2002CB613505)the National Natural Science Foundation of China (Gratn No. 90206046) National Center for Nanoscience and Technology of China
文摘Anodic aluminum oxide (AAO) membranes with large ordered pore domains were successfully prepared by adopting the anneal pre-treatment of polycrystalline alu- minum sheets. A statistical method with Gaussian distribution was introduced to quantitatively study the size of the domain with ordered pores. The largest average area of ordered pore domains was 2.6 μm2±0.11 μm2. The corresponding AAO membrane was synthesized by aluminum sheets annealed at 893 K for 24 h.