Growth of High-Quality Arbitrary-Shape Compound Semiconductors on Non-Epitaxial Substrates for Photovoltaic and Optoelectronic Device Applications

A method for direct growth of optoelectronic quality III-V semiconductors on non-epitaxial substrates will be discussed. Specifically, structures with geometries ranging from micro/nanostructures to ultra-large grain polycrystalline thin films may be grown via a phase transformation technique where the group III element is first deposited in the desired geometry and subsequently exposed to a vapor of the group V element. By careful control over nucleation and growth of the resulting III-V semiconductor, arbitrarily shaped III-V structures may be grown on non-epitaxial substrates. First, the general method for this growth will be discussed, showing how different structures and geometries may be obtained using InP as a model system. Next characterization of the InP films obtained will be presented, showing that films grown via this method on metal foils exhibit mobilities of ~500 cm^2/V-s, minority carrier lifetimes of >2 ns, and radiative efficiencies comparable to single crystal InP wafers. Additionally, methods for control over nucleation are demonstrated, showing that single crystalline structures >100 um in diameter may be easily obtained and, with proper tuning, mm scale crystals may be grown on non-epitaxial substrates. Furthermore, the use of this nucleation and growth control will be used to demonstrate InP for electronic and optoelectronic applications.