The present invention relates to devices, particularly photovoltaic devices, incorporating Group IIB / VA semiconductors such phosphides, arsenides, and / or antimonides of one or more of Zn and / or Cd. In particular, the present invention relates to methodologies, resultant products, and precursors thereof in which electronic performance of the semiconductor material is improved by causing the Group IIB / VA semiconductor material to react with at least one metal-containing species (hereinafter co-reactive species) that is sufficiently co-reactive with at least one Group VA species incorporated into the Group IIB / VA semiconductor as a lattice substituent (recognizing that the same and / or another Group VA species also optionally may be incorporated into the Group IIB / VA semiconductor in other ways, e.g., as a dopant or the like).