Dependence of carrier localization in InGaN∕GaN multiple-quantum wells on well thickness

Abstract

Carrier localization in InGaN∕GaN multiple-quantum wells (MQWs) with three different well thicknesses was investigated optically using time-integrated and time-resolved microphotoluminescence spectroscopy. An anomalous temperature dependence of the photoluminescence peak energy was observed, as a consequence of local potential fluctuations. The carrier localization was more prominent in the case of MQWs with wide well thickness. The results indicate that the degree of potential fluctuation increases with increasing well thickness. Emission from quantum-dot-like states only became apparent in MQWs with wide well thickness, which supports the assertion that carrier localization in InGaN∕GaN MQWs is due to the formation of quantum dots.

Influence of quantum well inhomogeneities on absorption, spontaneous emission, photoluminescence decay time, and lasing in polar InGaN quantum wells emitting in the blue-green spectral region

“…3. It is worth noting that the localized character of PL is expected at low temperatures for this material system even for high quality QWs [40][41][42]. The importance of non-radiative recombination is difficult to discuss in this case since the mechanism of non-radiative recombination is suppressed at low temperatures, i.e., τ nr τ r .…”

Temporally and spatially resolved photoluminescence investigation of (112¯2) semi-polar InGaN/GaN multiple quantum wells grown on nanorod templates

“…This has also been observed on InGaN/GaN MQWs grown on free-standing GaN substrates. [9][10][11][12][13] A standard two exponential component model is used to study excitonic dynamics, and thus TRPL traces [I(t)] can be described by [16][17][18] IðtÞ ¼ A 1 expðÀt=s 1 Þ þ A 2 expðÀt=s 2 Þ:…”

Efficiency enhancement of InGaN/GaN multiple quantum wells with graphene layer

“…The biexponential fit comprises a fast decay component s 1 describing delocalized exciton recombination and a slow decay component s 2 describing communication between localized states [24]. At room temperature, the two samples show I 1 (0) ) I 2 (0), indicating that s 1 can be taken as the representative decay lifetime s PL .…”

“…4, the decay traces of TRPL spectra show nonsingle exponential forms, and a standard two exponential component model is used to study excitonic dynamics. And thus the TRPL traces can be fitted by the following exponential decay expression [23,24]:…”