UHV-STM study of single-walled carbon nanotubes applied to the GaAs(110) and InAs(110) surfaces

In this study, ultrahigh vacuum (UHV) cross-sectional scanning tunneling microscopy (STM) and spectroscopy (STS) were used to probe the physical and electrical properties of individual single-walled carbon nanotubes (SWNTs) deposited onto semiconducting GaAs and InAs platforms. Isolated nanotubes were applied to the III-V(110) surface in situ via an UHV-compatible dry contact transfer (DCT) process. Subsequent STM observations indicate a substrate-dependent SWNT orientation, with individual nanotubes exhibiting a tendency to align in the $<\overline 1 10>$ direction, parallel to surface sublattice rows, while STS measurements confirm the Type I and Type II energy band alignments of the GaAs/SWNT and InAs/SWNT systems, respectively. Additionally, the electronic character of a naturally occurring intramolecular semiconducting/metallic SWNT junction is profiled