A novel model on time-resolved photoluminescence measurements of polar InGaN/GaN multi-quantum-well structures

Abstract

Based on carrier rate equation, a new model is proposed to explain the non-exponential nature of time-resolved photoluminescence (TRPL) decay curves in the polar InGaN/GaN multi-quantum-well structures. From the study of TRPL curves at different temperatures, it is found that both radiative and non-radiative recombination coefficients vary from low temperature to room temperature. The variation of the coefficients is compatible with the carrier density of states distribution as well as the carrier localization process. These results suggest that there is a novel method to calculate the internal quantum efficiency, which is a complement to the traditional one based on temperature dependent photoluminescence measurement.

Kinetics of the radiative and nonradiative recombination in polar and semipolar InGaN quantum wells

“…This temperature relation is frequently used up to date. For instance, Okamoto et al 23 suggested that internal quantum efficiency of InGaN quantum wells reached 100% at 10 K. Similarly, the authors from other group experimentally determined nonradiative lifetimes in InGaN quantum wells, always showing strong increase at low temperature [24][25][26][27] . Although we are aware, that there is a possibility of the existence of a certain nonradiative recombination at very low temperature by for example multiphonon emission.…”

A Review on Experimental Measurements for Understanding Efficiency Droop in InGaN-Based Light-Emitting Diodes

“…It is should be pointed out that, in some semiconductors [ 64 , 65 ], radiative recombination can be described as Bn , wherein n denotes the exciton concentration. However, according to the latest carrier dynamics study in InGaN multi-quantum-well (MQW) [ 66 ], the radiative recombination is bimolecular recombination rather than exciton recombination and should be described as Bn 2 . The work by Badcock et al has pointed out that it is the uncorrelated localization nature of electrons and holes that leads to a Bn 2 recombination description [ 67 ].…”

Study on Optical Properties and Internal Quantum Efficiency Measurement of GaN-based Green LEDs

“…In PDPL experiment, integrated intensities at different excitation power are recorded and the variation curves between excitation power and integrated intensities is fitted in terms of ABC model to acquire the relationships between coefficients of different recombination channels [12], which will be explained in detail later. Ultrafast lasers are used in TRPL to obtain photoluminescence (PL) decay curves after excitation, whose mechanism is intricate and controversial [13][14][15][16][17]. The measurement of IQE is challenging, since it cannot be measured directly, and different indirect means have their own problems and scope of application, for example, assuming IQE value is equal to 100% at LT is unreasonable in TDPL method.…”