Effect of growth temperature of GaN:Mg layer on internal quantum efficiency of LED structures with InGaN/GaN quantum wells

Abstract

It is shown that increasing of growth temperature of p-GaN layer in temperature range 940-1060 °C leads to decreasing of internal quantum efficiency due to diffusion of magnesium atoms from p-GaN into quantum wells. At the electroluminescence regime quantum efficiency of samples with low temperature p-GaN is limited by insufficient crystal quality or low solubility of magnesium in emitter layer.

The Effect of Imbalanced Carrier Transport on the Efficiency Droop in GaInN-Based Blue and Green Light-Emitting Diodes

“…To preserve the integrity of the high-In-content GaInN active region, the growth temperature for the subsequently grown p-type GaN layer is lowered for green LEDs. The following characteristics of green LEDs with a p-type GaN layer grown at a lower temperature are noteworthy: First, p-type doping is limited by the lower solubility of magnesium (Mg) in the GaN cladding layer of green LEDs, resulting in a lower equilibrium hole concentration p p0 in the p-type layer when compared to blue LEDs [20]. Second, grain boundaries and defects are more abundant for p-type GaN layers grown at lower temperatures, and thus the p-type GaN cladding layer has a poor hole mobility µ p while the electron concentration n and mobility µ n in the n-type GaN cladding layer of green LEDs are the same as those in blue LEDs [21].…”