Polycrystalline indium phosphide on silicon using a simple chemical route

We describe a simple, aqueous and low thermal budget process for deposition of polycrystalline indium phosphide on silicon substrate. Using stoichiometric indium oxide films prepared from its spin-coated precursor on silicon as an intermediate step, we achieve stoichiometric indium phosphide films through phosphidisation. Both indium oxide and indium phosphide have been characterized for surface morphology, chemical composition, and crystallinity. The morphology and crystalline structure of the films have been explained in terms of the process steps involved in our deposition method. Incomplete phosphidisation of indium oxide to indium phosphide results in the restructuring of the partly unconverted oxide at the phosphidisation temperature. The optical properties of the indium phosphide films have been analyzed using micro photoluminescence and the results compared with those of a homoepitaxial layer and a theoretical model. The results indicate that good optical quality polycrystalline indium phosphide has been achieved. The Hall measurements indicate that the carrier mobilities of our samples are among the best available in the literature. Although this paper presents the results of indium phosphide deposition on silicon substrate, the method that we present is generic and can be used for deposition on any suitable substrate that is flexible and cheap which makes it attractive as a batch process for photovoltaic applications.