Absence of surface stress change during pentacene thin film growth on the Si(111)-(7 × 7) surface: a buried reconstruction interface

Abstract

We use high-resolution surface stress measurements to monitor the surface stress during the growth of pentacene (C22H14) on the (7×7) reconstructed silicon (111) surface. No significant change in the surface stress is observed during the pentacene growth. Compared to the changes in the surface stress observed for Si and Ge deposition on the Si(111)-(7×7) surface, the insignificant change in the surface stress observed for the pentacene growth suggests that the pentacene molecules of the first adsorbate layer, although forming strong covalent bonds with the Si adatoms, do not alter the structure of the (7×7) reconstruction. The (7×7) reconstruction remains intact and, with subsequent deposition of pentacene, eventually becomes buried under the growing film. This failure of the pentacene to affect the structure of the reconstruction may represent a fundamental difference between the growth of organic thin films and that of inorganic thin films on semiconductor surfaces.