Improvement of near-ultraviolet InGaN-GaN light-emitting diodes through higher pressure grown underlying GaN layers

The 410-nm near-ultraviolet (near-UV) InGaN-GaN multiple quantum-wells light-emitting diodes (LEDs) with low-pressure-grown (200 mbar) and high-pressure-grown (400 mbar) Si-doped GaN underlying layers were grown on c-face sapphire substrates by metal-organic vapor phase epitaxy. Increasing the growth pressure during the initial growth of the underlying n-type GaN epilayers of the near-UV InGaN-GaN LEDs was found to reduce the amount of threading dislocations that originated from the GaN-sapphire interfaces. The electroluminescence intensity of LEDs with underlying GaN layers grown at a higher pressure was nearly five times larger than that of LED with layers grown at lower pressure. Additionally, two-order reduction of leakage current was also induced for the LEDs grown at a higher pressure.