Berlin 2005 – scientific programme

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O: Oberflächenphysik

O 39: Nanostrukturen IV

O 39.6: Talk

Tuesday, March 8, 2005, 12:00–12:15, TU EB420

Annealing induced 2D nano-patterning of Ga/Si(111) studied by STM — •Subhashis Gangopadhyay, Thomas Schmidt, and Jens Falta — Institute of Solid State Physics, University of Bremen, P. O. Box 330440, Bremen 28334, Germany

Annealing induced two dimensional nano-patterning was observed on Si(111) after submonolayer deposition of Ga at room temperature (RT) followed by annealing cycles. The evolution of the surface structure was studied using variable temperature scanning tunneling microscope (VT-STM). After RT Ga deposition, self-organized Ga induced magic clusters are found. Excess Ga leads to the formation of small 2D islands. The magic clusters are thermally stable up to 400^∘C (transition temperature). Depending on Ga deposit, two types of 2D pattern formation are observed located at the surface steps and the domain boundaries of the former Si(111)-7×7 reconstruction. For Ga coverages below 1/3 ML, Si(111)-7×7 domains are surrounded by √3×√3-Ga structure which decorates the former domain boundary and step edges. If the Ga coverage exceed 1/3 ML, domains of √3×√3-Ga structure are found surrounded by a 6.3×6.3-Ga structure.