Coalescence of GaP on V-groove Si for III-V/Si Solar Cells

Here, we study the morphology and strain relaxationof GaP as it coalesces over V-groove Si. V-groove nanopatterning is a promising way to create substrates that enable the grow of high quality III-V on Si, and it offers a route to III-V growth on low-cost Si substrates rougher than those typically required for epitaxial growth. We find that even at optimized growth conditions, careful control of the geometry of the nanopatterns is needed to promote a smooth morphology of the III-V material. We also find that strain relaxation, which resulted in an elevated threading dislocation density, occurs during the coalescence process. With further dislocation reduction, the templates described here are promising for further development of III-V solar cells on Si. Additional work on growing these templates on low-cost, wet-polished Si will also be presented.