Contactlaag

Contactlaag, or contact layer, is a thin interfacial layer placed between a substrate and a subsequent film or coating. It is designed to tailor interactions at the interface, including adhesion, wettability, diffusion, and electrical or optical properties.

In coatings and paints, a contactlaag commonly acts as a primer or adhesion promoter to improve bonding of the topcoat to the substrate. In electronics and optoelectronics, interlayers serve to reduce diffusion, align energy levels, or improve electrical contact. In catalysis or corrosion protection, barrier interlayers prevent substrate degradation or undesired reactions.

Typical materials include silane coupling agents for organic/inorganic substrates, metal oxides (such as Al2O3 or TiO2) as diffusion barriers, and conductive or work-function–tuning layers such as thin metal films, graphene, or conductive polymers. Application methods vary: chemical grafting, sputtering (PVD), chemical vapor deposition, atomic layer deposition, or solution processing like spin coating or dip coating. The thickness ranges from a few nanometers to several hundred nanometers depending on function.

Key properties are chemical compatibility with both sides, appropriate thickness, uniformity, mechanical adhesion, thermal and chemical stability, and, if conducting, suitable conductivity and work function. Common evaluation methods include adhesion tests, microscopy (SEM, AFM), thickness measurement (ellipsometry, profilometry), and spectroscopy (XPS, SIMS).

Examples include primer layers in paint systems; adhesion promoters on metals or composites; diffusion barriers in microelectronics; and interlayers in solar cells and OLED stacks.