Auger recombination in InGaN measured by photoluminescence

Abstract

The Auger recombination coefficient in quasi-bulk InxGa1−xN (x∼9%–15%) layers grown on GaN (0001) is measured by a photoluminescence technique. The samples vary in InN composition, thickness, and threading dislocation density. Throughout this sample set, the measured Auger coefficient ranges from 1.4×10−30to2.0×10−30cm6s−1. The authors argue that an Auger coefficient of this magnitude, combined with the high carrier densities reached in blue and green InGaN∕GaN (0001) quantum well light-emitting diodes (LEDs), is the reason why the maximum external quantum efficiency in these devices is observed at very low current densities. Thus, Auger recombination is the primary nonradiative path for carriers at typical LED operating currents and is the reason behind the drop in efficiency with increasing current even under room-temperature (short-pulsed, low-duty-factor) injection conditions.

Effects of quantum well growth temperature on the recombination efficiency of InGaN/GaN multiple quantum wells that emit in the green and blue spectral regions

“…As the excitation power density is increased, the IQE values increase in a similar manner until at the highest excitation power densities, where the rate of increase slows until a plateau is reached, a behavior observed prior to the onset of efficiency droop. 32 Such progressive increases in IQE or PL intensity with increasing excitation density have been widely reported [32][33][34][35][36][37] and have been attributed to saturation of a non-radiative recombination pathway. 37 Above the excitation power density at which the IQE begins to reach a plateau, the behavior of samples blue 1 and blue 2 begins to diverge with the IQE of blue 2 reaching a stable IQE at a lower excitation power density than blue 1.…”

Carrier distribution in InGaN/GaN tricolor multiple quantum well light emitting diodes

“…High current densities lead to high carrier densities in the active region, and consequently a significant amount of nonradiative Auger recombination. 1 An increase in the internal quantum efficiency at higher current densities can be achieved by spreading the carriers over a larger volume, either through the employment of a double heterostructure or by using a multiquantum well ͑MQW͒ active region. 2 In a MQW configuration, it is important to have a uniform distribution of carriers across all the quantum wells.…”

Strain effects in group-III nitrides: Deformation potentials for AlN, GaN, and InN

“…For light emitting diodes (LEDs) 1 and laser diodes (LDs) 2,3 the group-III-nitrides are currently the only commercially available materials class for the green to the deep ultraviolet part of the spectrum, and future applications as chemical sensors, 4 in quantum cryptography 5 or in photocatalysis 6 are being explored. Applications in solid state lighting, however, are currently limited by loss mechanisms 7,8 and a deeper understanding of the fundamental materials properties is required. One crucial factor is the effect of strain.…”