The development of Cu pyramids on W(111)

M. J. Gladys1, I. Ermanoski1, G. Jackson1, J. S. Quinton1, J. E. Rowe2 and T. E. Madey1

1 Physics and Astronomy and Laboratory for Surface and Modification, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854-8019.

2 Physics Department, North Carolina State University, Raleigh, North Carolina 27695

Abstract

An intended study into surface reconstruction of 0.3ML Cu on W(111) with SXPS evolved into an investigation of thick Cu overlayers with STM and LEED. It was discovered that high dose rates of Cu onto W(111) at room temperature produced similar LEED patterns to that of the overlayer induced faceting of W(111) and Ir(210) substrates. The LEED patterns revealed elongated triangular pyramids of Cu superimposed on the 1x1pattern of the W(111) surface.
AES and SXPS showed a form of 3D growth of the Cu overlayers and subsequent STM images reinforced the LEED finding with pictures of large elongated triangular Cu pyramids on the planar W(111) surface.
It was also discovered with STM that at room temperature the Cu pyramids were more stable than layer films. A fascinating set of consecutive STM images showing growth of the Cu pyramids revealed not only is there a step potential to inhibit surface diffusion and hopping down of adatoms but Cu atoms must be either hopping up the step edge or involved in some sort of intralayer diffusion pushing the atoms up through the lower layer. Influence by the STM was concluded to be minimal.