Bert Stegemann

Instabilities and pattern formation during the self-organized growth of nanoparticles on graphite

Abstract Sb4-clusters have been deposited onto highly oriented pyrolytic graphite (0001), and the formation of larger antimony particles has been observed as a function of surface coverage by SEM. The initial morphology of the particles is nearly spherical, according to a Volmer–Weber type growth. At a radius of about 60 nm this geometry becomes unstable, and the particles transform into dendritic and viscous finger-like islands. We suppose that the driving force for this conversion is due to a supercooling of the particles, which itself arises from a size dependent amorphous to crystalline phase transition.

STM investigation of surface alloy formation and thin film growth by Sb4 deposition on Au(111)

The growth of thin antimony films on the Au(1 1 1) surface at room temperature is studied by scanning tunneling microscopy (STM) in ultrahigh vacuum. At coverages up to one monolayer nanometer-sized islands are formed on the Au(1 1 1) terraces. High resolution STM images of these islands allow the distinction of gold and antimony atoms and confirm the formation of a well-ordered surface alloy. Its symmetry and interatomic distances agree well with the unreconstructed (1 0 0) plane of the bulk compound AuSb2. With increasing antimony coverage amorphous layers grow on the alloy support. In the initial stage of the amorphous layer growth ordered regions with cubic lattice structure are found in the overall amorphous films. The measured lattice constants and symmetries of these local structures imply that they consist of undissociated Sb4 clusters. 2002 Elsevier Science B.V. All rights reserved.

INTERACTION OF MASS SELECTED ANTIMONY CLUSTERS WITH HOPG

Abstract We have investigated the interaction of positively charged antimony clusters Sb n + with HOPG as a function of cluster size (2xa0 n

Subsequent layer growth of supported nanoparticles by deposition of Sb4 clusters onto MoS2(0001)

The surface morphology after deposition of Sb4 clusters onto MoS2(0001) at 90xa0K has been studied in detail with scanning tunnelling microscopy in ultrahigh vacuum. It has been found that during the initial stage of growth two-dimensional nanoparticles are formed. With increasing coverage these nanoparticles grow layer by layer and each layer has the height of one monolayer of undissociated Sb4 clusters. The interface width (surface roughness) has been quantitatively determined as a function of total coverage. Ideal three-dimensional layer-by-layer growth has been identified for the single particles according to a Poisson distribution of exposed areas of the layers of the particles. Consequently, antimony grows on MoS2(0001) without interlayer diffusion which is suppressed by an effective step edge (Schwoebel-Ehrlich) barrier.