Add to ORKGApparatus and method for atomic layer deposition on a surface of a substrate (6) in a treatment space. A gas supply device (15, 16) is present for providing various gas mixtures to the treatment space. The gas supply device (15, 16) is arranged to provide a gas mixture with a precursor material to the treatment space for allowing reactive surface sites to react with precursor material molecules to give a surface covered by a monolayer of precursor molecules attached via the reactive sites to the surface of the substrate. Subsequently, a gas mixture comprising a reactive agent capable to convert the attached precursor molecules to active precursor sites is provided. A plasma generator (10) is present for generating an atmospheric pressure pl...