Transition from layer-by-layer to rapid roughening in the growth of DIP on SiO2

Combining atomic force microscopy (AFM) and in situ grazing incidence X-ray diffraction (GIXD) we study the morphology and in-plane structure of diindenoperylene (DIP) on SiO2 in the early stages of the growth. We unravel noticeable strain relaxation phenomena in the in-plane structure during the growth of the first layers, concomitant with a transition from layer-by-layer growth to rapid roughening at a certain critical thickness of about five monolayers.