Site-specific Forest-assembly of Single-Wall Carbon Nanotubes on Electron-beam Patterned SiOx/Si Substrates

摘要

Based on electron-beam direct writing on the SiOx/Si substrates, favorableabsorption sites for ferric cations (Fe3+ ions) were created on the surfaceoxide layer. This allowed Fe3+-assisted self-assembled arrays of single-wallcarbon nanotube (SWNT) probes to be produced. Auger investigation indicatedthat the incident energetic electrons depleted oxygen, creating more danglingbonds around Si atoms at the surface of the SiOx layer. This resulted in adistinct difference in the friction forces from unexposed regions as measuredby lateral force microscopy (LFM). Atomic force microscopy (AFM) affirmed thatthe irradiated domains absorbed considerably more Fe3+ ions upon immersion intopH 2.2 aqueous FeCl3 solution. This rendered a greater yield of FeO(OH)/FeOClprecipitates, primarily FeO(OH), upon subsequent washing with lightly basicdimethylformamide (DMF) solution. Such selective metalfunctionalizationestablished the basis for the subsequent patterned forest-assembly of SWNTs asdemonstrated by resonance Raman spectroscopy.