Nucleation layers for growth of III-nitride structures, and methods for growing the nucleation layers, are described herein. A semiconductor can include a silicon substrate and a nucleation layer over the silicon substrate. The nucleation layer can include silicon and deep-level dopants. The semiconductor can include a III-nitride layer formed over the nucleation layer. At least one of the silicon substrate and the nucleation layer can include ionized contaminants. In addition, a concentration of the deep-level dopants is at least as high as a concentration of the ionized contaminants.