Deposition and STM investigation of single-walled carbon nanotubes on GaAs(110)

We have applied single walled carbon nanotubes (SWNTs) to the cleaved GaAs(110) surface in ultra high vacuum using a dry contact transfer (DCT) procedure and studied the system using a scanning tunneling microscope (STM). STM images reveal a clean transfer of predominantly isolated SWNTs to the semiconductor surface, with minimal additional contamination to the substrate surface. Atomic features of the nanotubes and underlying substrate can be simultaneously resolved and suggest the preferential alignment of isolated SWNTs along the [110] direction on the GaAs surface. Scanning tunneling spectroscopy (STS) measurements reveal SWNT bandgaps contained wholly within the substrate gap, with the measured values of those energy gaps comparing favorably to theoretically predicted values.