Temperature dependence of surface roughening during homoepitaxial growth on Cu(001)

Abstract

X-ray scattering has been used to study the roughening of the Cu(001) surface during homoepitaxial growth, as a function of temperature. Between 370 and 160 K, the mean-square roughness σ2, obtained from specular reflectivity data, was found to increase as a power law σ2=Θ2β for coverages Θ, ranging from 3 to 96 ML. The roughening exponent β was observed to depend on the temperature of the substrate: it monotonically increases with decreasing temperature from β≈1/3 at T=370K to β≈1/2, at T=200K. At 110 K a smoother growth re-enters in the presence of a large vacancy concentration in the deposited film.