Methods of forming dense seed layers and structures thereof are provided. Seed layers including a monolayer of molecules having a density of about 0.5 or greater may be manufactured over a metal layer, resulting in a well-defined interface region between the metal layer and a subsequently formed material layer. A seed layer including a monolayer of atoms is formed over the metal layer, the temperature of the workpiece is lowered, and a physisorbed layer is formed over the seed layer, the physisorbed layer including a weakly bound layer of first molecules. A portion of the first molecules in the physisorbed layer are dissociated by irradiating the physisorbed layer with energy, the dissociated atoms of the first molecules being proximate the seed layer. The workpiece is then heated, causing integration of the dissociated atoms of the first molecules of the physisorbed layer into the seed layer and removing the physisorbed layer.