High quality nitride semiconductors grown on novel ScAlMgO4 substrates and their light emitting diodes

III-N semiconductors growth on high quality ScAlMgO4 (SCAMO) substrates was studied. The GaN epitaxial layer grown on the SCAMO substrate showed a low defect density of 5.6 × 107 cm−2 evaluated by cathode luminescence and had a distinct improvement in crystallinity compared to the GaN layer on a sapphire substrate. LEDs on both SCAMO and sapphire substrates were grown, and their optical properties were compared. The LED on the SCAMO substrate showed high luminescence efficiency by photoluminescence, and it was 14.3% at 300 K. Bright emission from the LED on the SCAMO substrate was observed under current injection and the electroluminescence properties revealed that the external efficiency of the LED on the SCAMO substrate was 15% higher than that of the LED on the sapphire substrate.