CORRELATIONS IN THE INTERFACE STRUCTURE OF LANGMUIR-BLODGETT-FILMS OBSERVED BY X-RAY-SCATTERING

X-ray scattering experiments within the region of total external refle ction as well as grazing-incidence-diffraction measurements from Langm uir-Blodgett films are shown. All measurements are explained quantitat ively using the distorted-wave Born approximation (small q(z) regions) or a simple kinematic scattering theory (large q(z) regions) for laye red systems. Since rather imperfect systems are investigated, strong v ertical correlations between the roughnesses of the organic layer inte rfaces were found for two samples consisting of 9 and 11 layers, respe ctively, of cadmium-arachidate on silicon (100) surfaces. This conform al roughness does not stem from the substrate but from defects and hol es of the first transferred layer. The model of self-affine rough inte rfaces yields consistent parameters compared with grazing incidence di ffraction experiments and no hints towards a cadmium-arachidate island formation are observed.