Interactions between PTCDI-C8 and Si(100) Surface

PTCDI-C8 molecules are vapor-deposited onto reconstructed Si(100)-(2 x 1) surface under ultra-high vacuum. X-ray photoelectron spectra reveal a bond formation between oxygen atoms of the molecules' carboxylic groups and Si dangling bonds of the substrate. Following PTCDI-C8 film growth, ultraviolet photoelectron spectra show a drop in the HOMO level with respect to the Fermi level from 1.8 eV to 2.0 eV and a monotonic work function increase from 2.5 eV up to 3.3 eV. For a film thickness of 6.0 nm, a difference of 1.5 eV between the HOMO level of the film and the valence band maximum of the substrate is accomplished.

Automated summary

PTCDI-C8 molecules were vapor-deposited onto reconstructed Si(100)-(2 x 1) surface in ultra-high vacuum. X-ray photoelectron spectra confirmed the bond formation between carboxylic group oxygen atoms of the molecules and Si dangling bonds of the substrate. After PTCDI-C8 film growth, ultraviolet photoelectron spectra showed a decrease in HOMO level and an increase in work function.