Abstract

Annealing a Bi-covered Si(001) surface at around 600C leads to significant Bi desorption, but the remaining Bi forms remarkable features on the surface: nanolines which are 1.5 nm wide, up to microns long and completely without kink or defect (when fully mature). The driving force behind the nanoline formation is a complex subsurface reconstruction known as the Haiku (it consists of 5- and 7-membered rings). The Bi nanolines, while remarkable, have a wider bandgap than the Si(001) surface; however, they are excellent candidates for nanoline templating. Overgrowth with In leads to a wetting behaviour, with a zigzag one dimensional III -V chain forming. Recent modelling suggests that Cu will attack the Bi-Si bonds, forming extended conducting wires one atom wide (in contrast to Ag, which forms islands on the nanolines). Recently, it has been shown that the Bi can be removed from the nanolines, leaving a Si-in-Si nanotemplate, which confirms the existence of the subsurface reconstruction, and has potential to act as a different template for nanowire growth. Bi nanolines can also be buried in crystalline silicon without losing their one-dimensional nature. I will present details of this fascinating system drawn from extensive experimental-theoretical collaborations.