Analysis of Internal Quantum Efficiency and Current Injection Efficiency in III-Nitride Light-Emitting Diodes

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

“…Several research groups reported that the polarization fields in the multi-quantum well (MQW) and electron blocking layer (EBL) enhance δ and thus facilitate electron leakage from the MQW into the p-type region, thereby causing a larger efficiency droop [6,12,13]. In addition, there have been several reports on the lack of hole injection and electron leakage being caused by a much lower concentration and mobility of holes compared to those of electrons, leading the authors to the conclusion that electron leakage contributes to the efficiency droop [14][15][16][17]. Furthermore, the onset current density of the efficiency droop, J Onset-of-droop , i.e., the current density where the peak point of the efficiency is found, can be expressed by the electron leakage model as [7]:…”

Performance enhancement of blue light-emitting diodes by using special designed n and p-type doped barriers

“…However, the haunting efficiency droop at high injection levels is still a large obstacle for InGaN/GaN LEDs to be competitive in terms of its high-brightness and high-power applications [3,4]. According to the literatures, people have proposed some possible physical mechanisms for efficiency droop such as the Auger recombination [5], poor hole injection efficiency [6], electron leakage [7], polarization effect [8], current crowding effect [9,10], the QCSE [7], and junction heating [11]. Among the above factors, poor hole injection in the active region and the resulting electron leakage are regarded as primary causes for this phenomenon [6,7].…”

“…According to the literatures, people have proposed some possible physical mechanisms for efficiency droop such as the Auger recombination [5], poor hole injection efficiency [6], electron leakage [7], polarization effect [8], current crowding effect [9,10], the QCSE [7], and junction heating [11]. Among the above factors, poor hole injection in the active region and the resulting electron leakage are regarded as primary causes for this phenomenon [6,7]. The large hole effective mass and the relatively small activation energy of Mg dopant in p-layers lead to undesired hole accumulation in the last quantum well (QW) close to the p-GaN side, resulting in the low radiative recombination rate in other QWs [12,13].…”

The role of photonics in energy

“…Another important issue is addressing the drop in efficiency at high current densities, known as efficiency droop, in InGaN-based LEDs. Several approaches based on new barrier designs for suppressing carrier leakage have been investigated to suppress the droop, [291][292][293][294][295] but complete suppression or removal of the droop requires suppression of Auger processes in the active region, [296][297][298] as indicated in Fig. 14.…”