Synthesis of peapods using substrate-grown SWNTs and DWNTs: an enabling step toward peapod devices.

We report the successful synthesis of nanoscale peapods from single-walled and double-walled nanotubes grown by chemical vapor deposition (CVD) on substrates with windows etched into free-standing silicon nitride membranes. CVD-grown nanotubes were oxidized in air, then filled with C(60) molecules from the vapor phase. Observed variation in nanotube oxidation and C(60) packing with nanotube diameter agreed with theoretical expectations. Windowed samples provide several important advantages for property measurements of peapods and other nanomaterials. Individual nanostructures can be followed through processing steps, and a single nanostructure can be inspected by high-resolution TEM and subsequently contacted with nanoscale electrodes using electron beam lithography.