Ultrahigh-vacuum scanning tunneling microscopy and spectroscopy of single-walled carbon nanotubes on hydrogen-passivated Si(100) surfaces

Single-walled carbon nanotubes (SWNTs) have been studied on a Si(100)-2×1:H surface using an ultrahigh-vacuum (UHV) scanning tunneling microscope (STM). Dry deposition of SWNTs in situ establishes the pristine interface necessary to elucidate fundamental physical and electronic interactions between SWNTs and silicon. We have achieved simultaneous atomic resolution STM images of isolated SWNTs and the local H-passivated Si(100) substrate. Scanning tunneling spectroscopy served to characterize both semiconducting and metallic SWNTs. In each case, electronic features unique to the nanotube can be identified within the substrate band gap. In contrast to previous UHV STM studies of SWNTs on Au(111), our investigation is motivated by the technological relevance of the Si(100) substrate and the potential for nanofabrication of hybrid SWNT-Si electronic devices on the Si(100)-2×1:H platform.