Ultrahigh vacuum (UHV) scanning tunnelling microscopy (STM) and spectroscopy (STS) have been used to examine the role of substrate doping and composition in determining the electronic behaviour of semiconducting single-walled carbon nanotubes (SWNT) deposited onto III-V(110) surfaces. Hybrid SWNT/III-V(110) systems were created through sample cleavage and subsequent nanotube transfer in UHV. Room temperature STS spectra indicate electron transfer from the n-GaAs substrate to the supported SWNT and from the SWNT to the p-GaAs substrate, resulting in the respective n-type and p-type doping of the nanotube upon adsorption. STS measurements on InAs(110) supported carbon nanotubes are less uniform, with selected SWNTs on the n-InAs(110) surface exhibiting distinct electronic changes when shifted into registration with the substrate lattice. No such orientation sensitivity is detected in nanotubes on GaAs surfaces. The potential for systematic modification of a SWNT's electronic behaviour through intentional substrate engineering could present a new avenue for the design and fabrication of nanotube-based device structures.
ASJC Scopus subject areas
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering
- Electrical and Electronic Engineering