Atomic-scale mechanisms of selective adsorption and dimerization of pentacene on Si surfaces

Abstract

We report results of first-principles calculations in terms of which we elucidate the mechanisms for nucleation and initial growth of pentacene films on Si. Pentacene molecules bond in flat, distorted configurations on bare surfaces. On H-passivated surfaces, direct bonding or H replacement are not energetically favored. However, molecules bond in an upright configuration at isolated depassivated Si dangling bonds and film growth continues over the passivated area. The results elucidate generic adsorption issues on inert surfaces and suggest procedures for controlling film growth.