Orientation and Ordering of Organic and Hybrid Inorganic–Organic Polyurea Films Using Molecular Layer Deposition

Abstract

The molecular orientation and ordering of films produced by a vapor-phase deposition technique known as molecular layer deposition (MLD) is investigated. Specifically, the influence of incorporating an inorganic component into MLD films is determined. Film growth properties and surface saturating conditions of a purely organic polyurea film and a mixed inorganic–organic polyurea film are investigated by in situ quartz crystal microbalance. Polarization-dependent X-ray absorption spectroscopy was employed to determine the orientation and ordering of these films. Both films demonstrate preferential orientation parallel to the substrate surface. However, the degree of ordering between the films is found to be starkly different. In-depth analysis revealed that the hybrid inorganic–organic films display a high degree of ordering compared to purely organic polyurea films. This study sheds light on the ability of MLD to finely tune oligomer packing density, growth rate, molecular orientation, and film ordering.