The efficiency of transformation of electricity into the light is a key point for HB LEDs. Efficiency of the typical LEDs achieves 40% to 50%. That means that more than 50% of the electrical power transforms into heat. The reason is a numerous of non-radiative recombination channels in the LEDs, because of high density of dislocations and point defects, and light extraction losses.
The strategic fight for LED high efficiency is the fight for high quality of the material and, in particular, for low dislocation density. Therefore, GaN or AlN substrates should be used to get high efficient HB LEDs or low threshold LDs.
However, the shortest way to get HB LEDs today is to increase electrical power applied to the LEDs and to improve LEDs thermal management at the same time.
Commonly a single quantum well or multiple quantum wells are used as the active layer in LEDs. For fabrication of a highly efficient device the number of carriers recombined inside the active layer should be maximized and the number of carriers recombined outside the active layer should be minimized. This needs optimization of capture rates for electrons and holes into the active layer.