Formation and characterization of homogeneous and mixed self-assembled monolayers of peptides and alkanethiols on indium phosphide surfaces

This report describes the detailed characterization of alkanethiol and cysteine-terminated peptide layers on InP(100). Contact angle measurements, atomic force microscopy, X-ray photoelectron spectroscopy, and ellipsometry were performed. The surface characterization techniques showed that the composition of the mixed monolyers can be controlled through the concentration of each adsorbate solution. The surface coverage of the adsorbates on the InP(100) surface was lower than that of similar self-assembled monolayers (SAMs) on gold. The tilt angles for all adsorbates were higher than those of similar adsorbates on metal surfaces. The data from this report is important for the successful chemical functionalization of III-V semiconductor surfaces that are part of biosensor platforms such as light-emitting diodes.