Kinetic roughening during rare-gas homoepitaxy

Using an optical-reflectivity-difference technique, we monitored the growth of multilayer Xe films on a commensurate monolayer of Xe on Ni(111) from 35 to 60 K. A transition occurs near 40 K from rough growth at low temperature to quasi-layer-by-layer growth characterized by persistent oscillations in the reflectivity difference. We discuss this transition in terms of changes in the island formation process and the onset of second-layer nucleation. The Xe sticking coefficient at 40 K is obtained from the period of the oscillations in the reflectivity difference. We find that the sticking coefficient decreases with increasing film thickness at fixed Xe pressure.