Temperature and orientation dependence of kinetic roughening during homoepitaxy: A quantitative X-ray-scattering study of Ag

Kinetic roughening during homoepitaxial growth was studied for Ag(111) and Ag(001). For Ag(111), from 150 to 500 K, the rms roughness exhibits a power law, sigma proportional to t(beta) over nearly three decades in thickness. beta approximate to 1/2 at low temperatures, and there is an abrupt transition to smaller values above 300 K. In contrast, Ag(001) exhibits layer-by-layer growth with a significantly smaller beta. These results are the first to establish the evolution of surface roughness quantitatively for abroad thickness and temperature range, as well as for the case where growth kinetics are dominated by a step-ledge diffusion barrier.