Fabrication of Highly Ordered Anodic Aluminium Oxide Templates on Silicon Substrates
BROWN UNIV PROVIDENCE RI DIV OF ENGINEERING
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The controlled fabrication of highly ordered anodic aluminium oxide AAO templates of unprecedented pore uniformity directly on Si, enabled by new advances on two fronts -- direct and timed anodisation of a high-purity Al film of unprecedented thickness 50 micrometres on Si, and anodizing a thin but pre-textured Al film on Si, has been reported. To deposit high-quality and ultra-thick Al on a non-compliant substrate, a prerequisite for obtaining highly ordered pore arrays on Si by self-organisation while retaining a good adhesion, a specially designed process of e-beam evaporation followed by in situ annealing has been deployed. To obtain an AAO template with the same high degree of ordering and uniformity but from a thin Al film, which is not achievable by the self-organisation alone, pre-patterning of the thin Al surface by reactive ion etching using a free-standing AAO mask that was formed in a separate process was performed. The resultant AAOSi template provides a good platform for integrated growth of nanotube, nanowire or nanodot arrays on Si. Template-assisted growth of carbon nanotubes CNTs directly on Si was demonstrated via a chemical vapour deposition method. By controllably removing the AAO barrier layer at the bottom of the pores and partially etching back the AAO top surface, new CNTSi structures were obtained with potential applications in field emitter, sensors, oscillators and photodetectors.
- Electrical and Electronic Equipment
- Refractory Fibers
- Metallurgy and Metallography
- Inorganic Chemistry