Femtosecond Electron Dynamics in Dye-Functionalized 6H-SiC(0001)

Abstract

The functionalization of inorganic semiconductors with self-assembled monolayers (SAMs) of organic molecules provides versatile potential applications in, among others, specific sensors and molecular electronics. As many applications rely on the heterogeneous transfer of excited electrons from the organic molecule to the conduction band of the semiconductor, the influence of different linking molecules on the electronic coupling is of particular interest. Employing time-resolved two-photon photoemission (TR-2PPE), electron injection from the excited state of immobilized benzo[ghi]perylene-1,2-dicarboxylic anhydride into 6H-SiC crystals was investigated. Linkers of different length and conjugation were used to study the influence on the electronic coupling to the semiconductor. Static 2PPE measurements showed that the excited state of the chromophore was located between 0.7 and 1.0 eV above the conduction band minimum of SiC, slightly depending on the linker group and the stacking complexes. This energetic...