Characterization of mosaic structures in metamorphic InP layers grown in GaAs substrate by solid source molecular beam epitaxy

The out-of-plane mosaicity and mosaic twist in the metamorphic InP layers directly grown on the GaAs substrate by solid source molecular beam epitaxy have been characterized. It is found that the difference of mosaic twist among samples is not as significant as the out-of-plane mosaicity. Furthermore, these two kinds of mosaicity are not correlated with each other. The sample with the optimized metamorphic buffer scheme has shown less out-of-plane mosaicity and mosaic twist, which is consistent with its better material quality revealed by photoluminescence studies. These results will benefit the buffer layer design and optimization for metamorphic devices.