Proof of asymmetry in the Cd-arachidate bilayers of ultrathin Langmuir-Blodgett multilayer films via X-ray interferometry

Abstract

X-ray interferometry was used to study the profile structures of ultrathin Langmuir-Blodgett films of Cd-arachidate deposited on alkylated germanium/silicon multilayer substrates. The relative electron density profiles of the one, two and three bilayer films on the Ge/Si multilayer substrates, derived via X-ray interferometry employing a highly constrained, real space refinement algorithm, have shown the same kind of asymmetry in the bilayers of such ultrathin films deposited on alkylated silicon or alkylated glass, as derived less directly and described previously [1]. This paper demonstrates experimentally the power of the X-ray interferometry method [2] for solving an unknown structure by placing a known structure beside it, and furthermore proves the correctness of the upstroke-downstroke asymmetry in the Cd-arachidate bilayers due to the Langmuir-Blodgett deposition technique.