Direct MOVPE growth of semipolar (112¯2) AlxGa1−xN across the alloy composition range

• (11–22) oriented semipolar AlGaN nitride layers grown across the composition range directly on m-sapphire substrates.
• Comprehensive structural characterization including discussion of phase-purity, surface morphology and epilayer tilt.
• Polarization-resolved optical transmission measurements show interesting valence band ordering properties.

We report a simple direct route for the synthesis of high-quality semipolar (112¯2) AlGaN alloys across the composition range by metalorganic vapour phase epitaxy. We show that a single high-temperature growth step without the use of a low-temperature nucleation or buffer layer is a convenient way to grow high-quality (112¯2) AlGaN layers on m-plane sapphire substrate. We also report a detailed investigation of the microstructure and optical properties of these layers including phase-purity, surface morphology, epilayer tilt, and polarization-resolved optical transmission measurements.