Structure and self-assembly of alkanethiols on III-V semiconductor (1Â 1Â 0) surfaces

The angular (azimuthal and polar) resolved measurements reveal a substrate-dependent tilt of 34° from normal for InP and 15° for GaP. A unique feature observed on these systems is the complete alignment of the alkyl chains with respect to the azimuthal orientation. Further structural data confirm that this adsorbate system represents the case of a huge, single domain organic monolayer. We interprete this behaviour, which deviates strongly from the well known thiol films on gold, silver or copper, in terms of structural constraints and dangling-bond induced preorientation of the alkanethiol chains.