Growing antiphase domain free GaAs thin films out of highly ordered planar nanowire arrays on exact (001) silicon
We report the use of highly ordered, dense, and regular arrays of in plane GaAs nanowires as building blocks to produce antiphase domain free GaAs thin films on exact (001) silicon. High quality GaAs nanowires were grown on V grooved Si (001) substrates using the selective aspect ratio trapping concept. The 4.1% lattice mismatch has been accommodated by the initial GaAs, a few nanometer thick with high density stacking faults. The bulk of the GaAs wires exhibited smooth facets and a low defect density. An unusual defect trapping mechanism by a "tiara" like structure formed by Si undercuts was discovered. As a result, we were able to grow large area antiphase domain free GaAs thin films out of the nanowires without using SiO2 sidewalls for defect termination. Analysis from XRD o rocking curves yielded full width at half maximum values of 238 and 154 arc sec from 900 to 2000 nm GaAs thin films, respectively, indicating high crystalline quality. The growth scheme in this work offers a promising path towards