Evolution of thin Cu films on GaAs(110) towards atomically flat epitaxial overlayers

The morphology of thin copper films on cleaved GaAs(110) surfaces, deposited at 80 K with subsequent annealing, has been investigated at room temperature by means of scanning tunneling microscopy. Constant-current topographies, taken during 24 days, that illustrate different stages of the film evolution towards an atomically flat, epitaxial metal overlayer are presented here. We compare our results with low-temperature grown silver films on GaAs(110) and find similar morphologies as predicted by the model of "electronic growth." In contrast to the surface diffusion of Cu on Cu(111) single crystals and the kinetics of similarly prepared silver films on GaAs(110), a strongly increased film stability has been observed, which we ascribe to a high tensile strain in the metal overlayer. (C) 2004 American Institute of Physics.