Anodic Aluminum Oxide Nanotemplate Research Articles

Conducting atomic force microscopy studies on domain wall currents of Bi5 Ti3 FeO15 nanodots fabricated by anodic aluminum oxide nanotemplate and sol-gel process.

We investigated the local current characteristics of Bi5 Ti3 FeO15 (BTFO) nanodots on Nb-doped SrTiO3 substrates affected by their ferroelectric domain structures and domain walls. The BTFO nanodots with a diameter of about 50 nm were fabricated by anodic aluminum oxide nanotemplates and a BTFO sol-gel process. Based on a piezoresponse force microscope, it was confirmed that domain walls were formed in the ferroelectric domain structures of the epitaxial BTFO nanodots. Current changes due to ferroelectric tunneling junctions according to ferroelectric polarizations in epitaxial BTFO nanodots were confirmed by conduction atomic force microscopy. In particular, the domain walls formed in the epitaxial BTFO nanodots formed high currents compared to the currents in ferroelectric tunneling junctions due to polarizations. RESEARCH HIGHLIGHTS: Ferroelectric Bi5 Ti3 FeO15 nanodots with a diameter of 50 nm. Ferroelectric domain structures observed with piezoresponse force microscopy. High domain wall currents observed at domain boundaries observed with conducting atomic force microscopy.

Three-Dimensional Nb Nanopillar based Electrode for Energy Storage Devices

In this study, aluminum (Al) film with high purity was coated on the Niobium (Nb) sheet by thermal evaporation under ultra-high vacuum. An Anodic Aluminum Oxide (AAO) nanotemplate was prepared on the Nb sheet. During AAO nanotemplate preparation, three-dimensional (3D) Nb nanopillars were grown on the Nb sheet. We performed a simple 3D Artificial Intelligence (AI) analysis of Nb nanopillars. According to the experimental results, the width of the prepared Nb nanopillars is in the range of 100–120 nm, and the length is approximately 150 nm. The Electron Diffraction Spectroscopy (EDS) results confirmed that the nanopillars are Nb. The prepared Nb nanopillars can be a potential candidate for energy storage applications.

Formation of ferroelectric multi-domains and electrical conduction in epitaxial BiFeO3 nanodots fabricated with AAO nanotemplates

The electrical conduction property of ferroelectric domains formed in nanoscale dots is an important issue for miniaturized non-volatile random access memory applications. Herein, the conduction characteristics of ferroelectric domain structures formed in epitaxial BiFeO3 (BFO) nanodots are evaluated. Nanoscale BFO dots are fabricated on Nb-doped SrTiO3 (Nb:STO) substrates using an anodic aluminum oxide (AAO) nanotemplate, spin-coating, and etching processes. Using various sizes, such as 65 nm, 50 nm, and 35 nm, of the BFO nanodots, the domain wall current and the current that is dependent on the direction of polarization are measured. A piezoresponse force microscope study reveals that multiple ferroelectric domains coexist in one BFO nanodot. A large current is measured using a conducting atomic force microscope at the domain wall location in the ferroelectric domains. After ferroelectric polarization switching of the domains, the current is slightly dependent on the polarization direction. The electrical resistance state is dependent on the presence or absence of domain walls within the ferroelectric domains of the BFO nanodots.

Broadband titanium nitride disordered metasurface absorbers

We experimentally demonstrate titanium nitride (TiN) broadband metasurface perfect absorbers by conformally coating plasmonic TiN films onto disordered anodic aluminum oxide (AAO) nanotemplates. The disordered metasurface absorbers exhibit polarization-insensitive and weak angle-dependent perfect absorption over the entire visible and near-infrared spectral regions (300 < λ < 2500 nm). We show from experimental results and numerical simulations that the light scattering induced by the strong disorder of the AAO nanopores and the strong absorption of the TiN deposited on their sidewall are of critical importance for achieving broadband perfect absorption. The TiN disordered metasurface perfect absorbers are superior to many other types of broadband perfect absorbers previously reported and are more suitable for practical applications especially in harsh environments. The device concept for broadband perfect absorption based on plasmonic metal-nitride film coated disordered dielectric media could potentially be extended to significantly enhance the efficiency of solar energy harvesting and the performance of hot-carrier based optoelectronics.

Fabrication of Nb nanopin electrodes and their influence on multiferroic properties of BiFeO3 thin films

We report enhanced multiferroic properties of BiFeO3 (BFO) thin films by depositing them on Nb nanopin bottom electrodes via spin-coating. The well-aligned Nb nanopin array was prepared from wet etching of an anodic aluminum oxide (AAO) nanotemplate. X-ray diffraction (XRD) measurement revealed that the BFO thin films were polycrystalline. The BFO thin films fabricated on Nb nanopin electrodes exhibited improved ferroelectricity with a remnant polarization (Pr) of 37.5 μC/cm2 and a coercive electric field (Ec) of 98 kV/cm, which was better than those (Pr ~ 32.9 μC/cm2 and Ec ~ 217 kV/cm) on the Nb film electrodes. We investigated leakage current, polarization switching speed as well as ferromagnetism, which also exhibited the improvement of BFO thin films on Nb nanopin electrodes. Significantly, we suggest that an enhanced electric field and surface-volume ratio of the Nb nanopin electrodes contribute to enhancement of the multiferroic properties of the BFO thin films.

Cost-Effective and High-Throughput Plasmonic Interference Coupled Nanostructures by Using Quasi-Uniform Anodic Aluminum Oxide

Large-area and uniform plasmonic nanostructures have often been fabricated by simply evaporating noble metals such as gold and silver on a variety of nanotemplates such as nanopores, nanotubes, and nanorods. However, some highly uniform nanotemplates are limited to be utilized by long, complex, and expensive fabrication. Here, we introduce a cost-effective and high-throughput fabrication method for plasmonic interference coupled nanostructures based on quasi-uniform anodic aluminum oxide (QU-AAO) nanotemplates. Industrial aluminum, with a purity of 99.5%, and copper were used as a base template and a plasmonic material, respectively. The combination of these modifications saves more than 18 h of fabrication time and reduces the cost of fabrication 30-fold. From optical reflectance data, we found that QU-AAO based plasmonic nanostructures exhibit similar optical behaviors to highly ordered (HO) AAO-based nanostructures. By adjusting the thickness of the AAO layer and its pore size, we could easily control the optical properties of the nanostructures. Thus, we expect that QU-AAO might be effectively utilized for commercial plasmonic applications.

Growth control of carbon nanotubes using by anodic aluminum oxide nano templates.

Anodic Aluminum Oxide (AAO) template prepared in acid electrolyte possess regular and highly anisotropic porous structure with pore diameter range from five to several hundred nanometers, and with a density of pores ranging from 10(9) to 10(11) cm(-2). AAO can be used as microfilters and templates for the growth of CNTs and metal or semiconductor nanowires. Varying anodizing conditions such as temperature, electrolyte, applied voltage, anodizing and widening time, one can control the diameter, the length, and the density of pores. In this work, we deposited Al thin film by radio frequency magnetron sputtering method to fabricate AAO nano template and synthesized multi-well carbon nanotubes on a glass substrate by microwave plasma-enhanced chemical vapor deposition (MPECVD). AAO nano-porous templates with various pore sizes and depths were introduced to control the dimension and density of CNT arrays. The AAO nano template was synthesize on glass by two-step anodization technique. The average diameter and interpore distance of AAO nano template are about 65 nm and 82 nm. The pore density and AAO nano template thickness are about 2.1 x 10(10) pores/cm2 and 1 microm, respectively. Aligned CNTs on the AAO nano template were synthesized by MPECVD at 650 degrees C with the Ni catalyst layer. The length and diameter of CNTs were grown 2 microm and 50 nm, respectively.

Fabrication of carbon nanostructures from polymeric precursor by using anodic aluminum oxide (AAO) nanotemplates

Anodic aluminum oxide (AAO) nano-templates are used in many fields of nanotechnology, particularly for use in creation of nanowires and nanotubes. In this research, the method for fabricating AAO nano-templates in two different electrolyte solutions (sulfuric acid and oxalic acid) via two step anodization procedure is presented. The influence of parameters related to both anodization steps such as the electrolyte, solution temperature, voltage and time on the pore size, porous distance and pore density was investigated. Scanning electron microscopy (SEM) images of the nano-templates also pointed out the effectiveness of this anodization method. The synthesis of carbon nanostructures from a polymeric precursor such as epoxy via fully filling the nanoporous AAO templates is reported. The prepared nanowires and nanotubes have been characterized by transmission electron microscopy (TEM), Raman spectroscopy and SEM. The results show the typical morphology and properties of multiwall carbon nanotubes and other nanostructures.

Enhanced osteogenic fate and function of MC3T3-E1 cells on nanoengineered polystyrene surfaces with nanopillar and nanopore arrays

During in vitro culture, cell fate and function, including cell adhesion, morphology, proliferation and differentiation, are affected by surface characteristics, such as geometry, wettability, hardness, chemistry and charge. This study replicated two different types of nanoengineered polystyrene surfaces (NPS) containing nanopillar (NPS-Pi) or nanopore (NPS-Po) arrays by hot embossing and investigated their topographical effects on cell behavior using osteoblast-like MC3T3-E1 cells. To mass-replicate NPS, rigid metal nano-stamps were manufactured by nickel electroforming onto two different nano-templates: (1) a nanopore-arrayed anodic aluminum oxide nano-template using two-step electrochemical oxidation and (2) a nanopillar-arrayed polymer using hot embossing process. The physical and mechanical properties of the NPS, including geometry, wettability, hardness and elastic modulus, were evaluated with the help of field emission-scanning electron microscopy, a contact angle meter, and a nanoindenter. The nanotopography maintained the bulk property, while drastically changing the surface properties. In vitro the NPS had significant effects on MC3T3-E1 cell morphology, attachment, proliferation and osteogenic differentiation compared to a flat substrate due to the altered physical and mechanical surface properties of the nanoengineered surface. Interestingly, the NPS-Po was more effective at enhancing cell proliferation and osteogenesis differentiation. One potential explanation for these results may be that the subcellular binding sites induced by the nanostructures changed the cell morphology and promoted contractile cytoskeletons, thereby enhancing osteogenic differentiation. This, which allows for the cost-effective replication of NPS and the control of cell behavior, has various applications with respect to biomedical and cell surface interaction studies, in addition to enhanced osteogenic cell fate and function.

Preparation of anodic aluminum oxide (AAO) nano-template on silicon and its application to one-dimensional copper nano-pillar array formation

Anodized aluminum oxide (AAO) nanotemplates were prepared using the Al/Si substrates with an aluminum layer thickness of about 300 nm. A two-step anodization process was used to prepare an ordered porous alumina nanotemplate, and the pores of various sizes and depths were constructed electrochemically through anodic oxidation. The optimum morphological structure for large area application was constructed by adjusting the applied potential, temperature, time, and electrolyte concentration. SEM investigations showed that hexagonal-close-packed alumina nano-pore arrays were nicely constructed on Si substrate, having smooth wall morphologies and well-defined diameters. It is also reported that one dimensional copper nanopillars can be fabricated using the tunable nanopore sized AAO/Si template, by controlling the copper deposition process.

Controlled Growth of Carbon Spheres by Chemical Vapor Deposition Based on Anodic Aluminum Oxide Nano-Template

The reactions were carried out by decomposing acetylene at 1000 °C in a two-stage furnace system for 10 min. In the first furnace no catalyst was placed and an AAO template with the average diameter about 50 nm was placed in the second furnace whose temperature was designed to be 500 °C, 600 °C and 700 °C. The samples were characterized by scanning electron microscopy and high resolution transmission electron microscopy. The results show that carbon spheres with average diameter about 50 nm on the AAO template surface were obtained when the temperature of the second furnace was designed to be 700 °C. These carbon spheres are composed of unclosed graphene layers with an interlayer distance of 0.33–0.35 nm between the layers.

Magnetic NiFe/Au barcode nanowires with self-powered motion

NiFe/Au barcode nanowires were synthesized by pulsed electrodeposition using anodic aluminum oxide nanotemplate, comprising magnetic, catalytic, and optical segments, respectively. The self-powered motion of the BNWs due to the catalytic reaction was observed in aqueous H2O2. The approach demonstrates how sophistication in barcode nanoarchitecture can be used to synthesize a wide range of hybrid materials.

Controllable Synthesis of Carbon Spheres Based on Anodic Aluminum Oxide Nano-Template

The reactions were carried out by decomposing acetylene at 1000 °C in a two-stage furnace system for 10 min. In the first furnace no catalyst was placed and an AAO template with average diameter about 50 nm was placed in the second furnace whose temperature was designed to be 700 °C. The samples were characterized by scanning electron microscopy and high resolution transmission electron microscopy. The results show that carbon spheres with average diameter about 50 nm on the AAO template surface were obtained and these carbon spheres are composed of unclosed graphene layers with an interlayer distance of 0.33–0.35 nm between the layers.

Modification and Formation Control of Anodic Aluminum Oxide (AAO) Nano-Templates Synthesized in Oxalic Acid Solution

not Available.

Modification and Formation Control of Anodic Aluminum Oxide (AAO) Nano-Templates Synthesized in Oxalic Acid Solution

not Available.

The Application of Atomic Layer Deposition for Low Dimensional Nanomaterial Synthesis

Atomic layer deposition (ALD) has been considered as a promising thin film deposition technique for nanoscale semiconductor device fabrication. Recently, however, the exclusive benefits of ALD make it viable tool for nanotechnology. In this presentation, I will present several examples on the application of ALD for low dimensional nanomaterials synthesis aiming at the next generation electronics. Due to its excellent conformality, ALD is an ideal technique to produce nanomaterials with combination of nanopatterning techniques. Utilizing highly conformal ZnO ALD on the nanohole arrays made by anodized aluminum oxide nanotemplates, low dimensional nanostructures were fabricated. And the constructed nanostructure were applied to fabricate high performance gas sensor. Also, by applying highly conformal ALD processes for transition metals followed by annealing, silicide nanowires were synthesized. Moreover, by adding SiH4 to the NH3 plasma reactant during Co plasma-enhanced ALD process, Co nanorod array was formed on Si substrates without using nanotemplates.

NiO Resistive Random Access Memory Nanocapacitor Array on Graphene

In this study, a NiO RRAM nanocapacitor array was fabricated on a graphene sheet, which was on a Nb-doped SrTiO(3) substrate containing terraces with a regular interval of about 100 nm and an atomically smooth surface. For the formation of the NiO RRAM nanocapacitor (Pt/NiO/graphene capacitor) array, an anodic aluminum oxide (AAO) nanotemplate with a pore diameter of about 30 nm and an interpore distance of about 100 nm was used. NiO and Pt were subsequently deposited on the graphene sheet. The NiO RRAM nanocapacitor had a diameter of about 30 +/- 2 nm and a thickness of about 33 +/- 3 nm. Typical unipolar switching characteristics of the NiO RRAM nanocapacitor array were confirmed. The NiO RRAM nanocapacitor array on graphene exhibited lower SET and RESET voltages than that on a bare surface of Nb-doped SrTiO(3).

스퍼터 증착된 알루미늄 박막을 이용한 양극산화 알루미늄 나노템플레이트 제조

Anodic aluminum oxide (AAO) nanotemplates for nano electronic device applications have been attracting increasing interest because of ease of fabrication, low cost process, and possible fabrication in large area. The size and density of the nanostructured materials can be controlled by changing the pore diameter and the pole density of AAO nanotemplate. In this paper, nano porous alumina films AAO nanotemplate was fabricated by second anodization method using sputterd Al films. In addition, effects of electrolyte temperature and anodization voltate on the microstructure of porous alumina films were investigated. As the electrolyte temperature was increased from to , the growth rate of nanoporous alumina films was increased from 86.2 nm/min to 179.5 nm/min. The AAO nanotemplate fabricated with optimal condition had the mean pore diameter of 70 nm and the pore depth of .

Synthesis and optimization of porous anodic aluminum oxide nano-template for large area device applications

A simplified anodized aluminum oxide (AAO) nano-template fabrication process was developed in this study, which can be suited for the large area device applications. The pores of various sizes and depths were realized from the thin (less than 1 µm) aluminum film deposited on the sapphire substrate. The optimum morphological structure was obtained by adjusting the applied voltage, types of acid solution, its concentration and temperature which has evolved after two phases of anodization followed by chemical etching. The Ar plasma pre-treatment method was developed and applied to improve the surface roughness of thin aluminum film without severely sacrificing the deposited layer thickness.

Fabrication of anodic aluminum oxide nanotemplate and investigation of their anodization parameters

Anodic Aluminum Oxide (AAO) nanotemplate, is a kind of layer made by anodizing a thin film of aluminum on a substrate. It contains alternate arrays and pores in the dimension of nanometer scale, which is currently being used to fabricate nano devices, magnetic nanostructures, polymeric nanowires, super conductors and nanofibers. This structure contains orderly columnar hexagonal porous cells. In this research, we have fabricated AAO nanotemplates on glass and pure aluminum substrate. In our research we have kept the temperature, concentration and voltage constant but the time was a variable. We observed that the dimensions of hexagonal pores increased with a linear speed of 100 nm per hour. Also the effect of annealing on the nanostructure is investigated. After analyzing annealed structure, it was observed that it is homogenous.