“The self assembly of well defined clusters is an alternative route to creating mono-dispersed nano-sized structures on surfaces of materials. The unique stability of these structures allows us to harness them as potential building blocks for nano-scopic devices or as templates for nano-fabrication” said Assoc. Prof. Eng Soon Tok, Deputy Director Surface Science Laboratory, Department of Physics, National University Singapore at a recent NANO Talk session at NANOTEC, Thailand. “This cluster characteristic is attributed to the collection of a “magic” number of adatoms which is found in metallic (e.g. Ag/Ag(100) and Pt/Pt(110)), semiconducting (e.g. Si/Si(111)) as well as mixed metal/semi-conducting materials (e.g. In/Si(001) and Ga, In, Ag, Mn or Pb/Si(111))”.
His research group have examine the formation and evolution of Si clusters on the Si(111) surface in terms of its origin, formation, interactions and dynamic behavior on the surface. The research demonstrated how to grow mono-disperse Si magic clusters of size ~ 13.5±0.5Å which also exhibit localized spatial ordering at the same time.
In addition, Prof. Tok also briefly talked about the dynamics of “Co-Si” cluster diffusion. He introduced the idea of a configuration dependent critical 2D nucleus which is directly responsible for the self alignment and assembly of magic clusters.
NANO Talk is a monthly public forum organized by NANOTEC for researchers and visiting professors to exchange knowledge and be updated on technology trends. Visiting professors to Thailand are encouraged to participate. To review past NANO Talk sessions, please log on: https://www.nanotec.or.th/en/?cat=11
