Nucleation and growth of tetracene films on silicon oxide

Tetracene film growth on SiO2 at room temperature via vacuum evaporation has been studied using ex situ atomic force microscopy. We demonstrate that tetracene films of layered morphology and good connectivity can be achieved on SiO2 under favorable growth conditions. Island size distribution analysis shows that tetracene nucleation in the optimal growth is diffusion mediated with a smallest stable cluster consisting of four molecules (i.e., the critical island size i=3). The film stability is sensitive to the film thickness. Postgrowth film structural evolution occurs on the time scale of minutes for the films at coverage less than three monolayers, while stable films become evident at coverage higher than three monolayers.