Comparative study of neutron reflectometry, X-Ray reflectometry and electrical impedance spectroscopy of organic films on silicon

Full text: A comparative study has been made of the substructure and properties of functionalized organic layers on silicon substrates, using neutron reflectivity, X-Ray reflectivity and low frequency electrical impedance spectroscopy (EIS). All three techniques have similar spatial structural resolution. X-Ray reflectometry provides information on the electron density of substructural layers whilst EIS provides data on the electric polarizability and electrical conductance properties of individual substructural layers. Neutron reflectivity likewise provides data on the atomic mass density of the layers. With organic films the contrast in neutron scattering for the elements of interest such as C, O, N is not very large. However, replacement of H2O with D2O allows a much enhanced contrast to be obtained and provides information in particular of the interdigitation of water molecules into film. This impinges on the polarizability and electrical conductance as as measured by EIS. (authors)