Phosphorus readily forms homoelement bonds in the solid state. Accordingly, over a hundred phosphorus-rich binary metal phosphides containing both P-P bonds and metal-P bonds have been synthesized in bulk form. Often, these compounds have semiconducting properties and decompose into elemental phosphorus and a metal-rich phosphide (with only metal-P bonds) at high temperatures. Thin-film synthesis of P-rich materials would help determine their technological potential and their compatibility with established materials and processes. In addition, growing these materials in thin-film form would be desirable for high-throughput characterization of their properties as a function of composition and process conditions. However, reports of polycrystalline P-rich phosphides as thin films are very scarce and seem to be limited to basic characterization of ZnP 2 and CdP 2 deposited by evaporation of powders of the pre-synthesized compounds. Thin-film growth from ela) Electronic mail: ancro@dtu.dk b) Electronic mail: andriy.zakutayev@nrel.gov emental or gaseous sources would significantly simplify the synthesis process.