III-V semiconductors are suitable for high efficiency and radiation resistant solar cells. However, the high cost of these materials limited the application of these solar cells only for specialty application. High quality polycrystalline III-V thin films on low cost substrate are the viable solutions for the problem. In this work we demonstrate two new approaches to grow polycrystalline InP on Si(001) substrate. (i) A simple chemical solution route which makes use of deposition of In2O3 on Si and its subsequent phosphidisation and (ii) In assisted growth that involves deposition of In metal on Si and subsequent growth of InP from its precursors in hydride vapor phase epitaxy. Both techniques are generic and can be applied to other semiconductors on low cost and flexible substrates.