Analysis of the GaN-rich side of GaNP using x-ray diffraction

Abstract

We investigated the growth of the GaN-rich side of GaNP films using metal-organic chemical-vapor deposition. The results of Auger electron spectroscopy suggest that phosphorus atoms incorporated into the film would be substituted on gallium sites rather than on nitrogen sites. Using x-ray diffraction, we have revealed that such GaNP films belong to a hexagonal system and that the relationship of the orientation between the GaNP film and its underlying GaN layer is [0001]GaNP‖[0001]GaN and [101¯0]GaNP‖[101¯0]GaN. Moreover, it was found that the lattice constants of GaNP were smaller than those of bulk GaN and there was no phase separation. We have also confirmed that the changes in these lattice constants were almost proportional to the phosphorus concentration included in the entire GaNP film thickness and that they decreased with an increase in the phosphorus concentration.