The use of the low-cost vapor-liquid-solid (VLS) crystal growth method in the manufacturing of III-V solar cell substrates has the potential to provide a lightweight, flexible, and cheaper alternative to traditional epitaxial-based substrates typical of state-of-the-art power generation technology. In this work, the VLS method is used to produce high-quality poly-crystalline indium phosphide (InP) on lightweight flexible metal foils. This novel method is expanded upon by growing materials with unique lattice constants. Compositions of In x Ga 1−x P are explored to target the lattice constant (5.8 A) identified as a promising candidate for surpassing 50% efficiency at 30 suns. X-ray diffraction results of preliminary trials verify the presence of InP and the absence of In confirming full phosphorization of In into InP. The photoluminescence spectra shows a correlation between the VLS grown InP sample and single crystal InP, both emitting at the InP bandedge of 1.337 eV.