Structural and optical properties of GaN1−xAsx grown by metalorganic chemical vapor deposition

GaN-based GaN1−xAsx alloys, x⩽0.043, were grown by metalorganic chemical vapor deposition. The results of high-resolution x-ray diffraction measurements indicated that no phase separation was observed over a range of up to x=0.043 and both the lattice constants c and a increased with an increase in arsenic composition. In cathodoluminescence measurements, the GaN1−xAsx showed a large band gap bowing parameter of 22.1eV. Furthermore, we have experimentally revealed that the valence band offset for the GaN1−xAsx∕GaN is very large, and we have proposed the band gap energy diagram of GaN1−xAsx utilizing an arsenic deep donor level.