Surface potential studies of self-assembling monolayers using Kelvin probeforce microscopy

The local contact potential difference (CPD) of different self-assembled n- alkanethiol monolayers on Au substrates has been measured using Kelvin prob e force microscopy (KPFM). Our results demonstrate that KPFM can be used to obtain topography and CPD information simultaneously. The measured CPDs sh ow a clear chemical contrast, allowing us to distinguish between thiol mole cules with different terminal groups, The CPD values of the same terminal g roup are found to vary with chain length, which is explained in the context of the dipole layer model. Copyright (C) 1999 John Whey & Sons, Ltd.