Silicon (Si) remains the key material for electronic devices. The ability to fabricate silicon in nanostructure form is important not only to the next generation of such devices, but also in other applications relying on enhanced surface area, low dimensionality, and structural control, such as photovolatics, battery technology, and biosensing/therapeutics. In this presentation, we describe the basic fabrication steps for arrays of silicon nanotubes (SiNTs) based on (1) deposition of silane (SiH4) on a preformed ZnO nanowire array template, followed by (2) sacrificial etching of the ZnO phase, resulting in the desired nanotube product. Hollow nanotube inner diameter is adjustable by size selection of the initial ZnO nanowire, while shell thickness control is achieved by concentration/duration of silicon deposition. Thermal annealing processes increase the crystallinity of the Si nanotubes; this crystallinity is reflected in the dissolution rate of the nanotube in water or phosphate-buffered saline (PBS).Relevant to ultimate applications, we have also carried surface functionalization of the nanotubes using well-known alkyl amine-terminated silicon alkoxide reagents in conjunction with a fluorescent probe such as fluorescein isothiocyanate (FITC). We have also demonstrated proof-of-concept in terms of nanotube loading relevant to guided drug delivery systems by incorporating several sizes of superparamagnetic iron oxide nanoparticles into a range of Si nanotube structures.All nanomaterials reported here were characterized by a combination of Scanning Transmission Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDX) and Transmission Electron Microscopy (TEM), along with confocal fluorescence microscopy in the case of the surface modified Si NTs.

Silicon nanotubes: Fabrication, surface functionalization, and loading

247th National Meeting (2014)

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