Fabrication of hexagonally ordered nanopores in anodic alumina: An alternative pretreatment

Abstract

Abstract. Anodic aluminum oxide (AAO) or anodic alumina template containing hexagonally ordered nanopores has been widely used over the last decade for the development of numerous functional nanostructures such as nanoscale sensors, computing networks and memories. The long range pore order requires the starting aluminum surface to be extremely smooth. Electropolishing is the most commonly used method for surface planarization prior to anodization. While prevalent, this method has several limitations in terms of throughput, polishing area and requirement of special experimental setups, which introduce additional speed bottlenecks in the intrinsically slow AAO-based nanofabrication process. In this work we report a new generation of the so-called -chemical polishing‖ approach which circumvents these stumbling blocks in the pretreatment phase and offers a viable, simpler, safer and faster alternative to electropolishing. These benefits are obtained without sacrificing the quality of the final AAO template. In this work we have (a) identified the optimum parameter regime for chemical polishing and (b) determined process conditions for which a novel parallel nanoridge configuration self-assembles and extends over a distance of several microns. Such patterns can be used as a mask for fabricating nanocrossbars, which are the main structural components in myriad nanoscale memories and crosspoint architectures.

Synthesis of alumino-silicates functionalized titanium as potential adsorbent: An industrial possibility

“…This ultimately decreases the diffusion path length of the adsorbent [5]. In addition, gradual uptake of Pb 2+ ion (49 %) was recorded at initial 10 minutes is due to the quick saturation of all empty active sites [1] and rapid diffusion of lead ions may accelerate the affinity of adsorbent to remove lead at initial time but quick decline after 10 minutes till 20 minutes is attributed to the surface coverage of alumino-silicate-Ti adsorbent results in the formation of metal complexes [10] (see Fig. 5.b) Comparative adsorption studies of alumino-silicates-Ti with both metals (lead and mercury) suggest Accordingly it can be found that regular incline is observed for the removal of mercury as compared to lead.…”

Understanding the Mechanisms that Affect the Quality of Electrochemically Grown Semiconducting Nanowires

“…To obtain a higher control of the nanowire dimensions and surface quality, an electrochemical self-assembly technique was used to fabricate a hexagonally ordered array of cylindrical nanopores on an aluminum substrate. Starting with high purity, unpolished and annealed aluminum (99.997%, AlfaAsar) foil with thickness of ~250 μm, the unpolished samples were first chemically polished [47] using 15 parts of 68% nitric acid and 85 parts of 85% phosphoric acid for 5 min at 850°C. The samples were then neutralized in 1 M sodium hydroxide (NaOH) for 20 min.…”

Магнитные свойства многослойных пленок Co/Pd на пористых темплатах Al-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=- с развитой субструктурой ячеек

“…• C в течение 24 h и химической по-лировке в растворе концентрированных азотной (68%) и фосфорной (85%) кислот [22]. Осажденная пленка алюминия анодировалась без предварительной обра-ботки.…”