Improved carrier confinement and distribution in InGaN light-emitting diodes with three-layer staggered QWs

Abstract

Compared with conventional InGaN Quantum Wells (QWs), staggered InGaN QWs offer improved optical and electronic properties. This work studied the carrier concentration, band structure, overlap of hole and electron wave functions, and polarization field of three-layer staggered QWs in the blue spectral region and analyzed them in detail theoretically to explore the source and the dominant mechanism for improvement. Although theoretical studies indicate that the polarization field in QWs of staggered InGaN QWs is larger, the carrier confinement effect is stronger, and the carrier distribution is more uniform. Therefore, three-layer staggered QWs can improve overlapping of the hole and electron wave functions and then enhance the recombination rate so as to increase the optical output power and electroluminescence intensity. Moreover, the performance of the staggered structure C with the lowest indium content at the center of the well is better than that of the step-staggered structure B.

Improved Performance of InGaN/AlGaN Multiple‐Quantum‐Well Near‐UV Light‐Emitting Diodes with Convex Barriers and Staggered Wells

“…[ 38 ] In addition, the Auger recombination coefficient and photon radiation recombination coefficient are 10 −11 cm 3 s −1 and 10 −31 cm 6 s −1 , respectively, which is the same as our previous research. [ 29 ] In addition, the Shockley–Read–Hall lifetime in the active region is set to be 10 nm. [ 39 ] The activation energy of Si donor and Mg receptor were set to be 20 moves and 200 MeV.…”

“…Up to now, some strategies for regulating band of QW and quantum barrier have been reported to ameliorate polarized electric field in MQWs active region and reduce the quantum confined stark effect for increasing the overlap of electron and hole wave functions: such as dual‐layer staggered quantum barrier with the graded Al composition, [ 17 ] three‐layer staggered quantum barrier, [ 18 ] dual‐triangle quantum barriers, [ 19 ] stepped quantum barrier with the graded In composition, [ 20,21 ] concave quantum barrier, [ 22 ] partial‐grade barriers, [ 23 ] InGaN barriers, [ 24 ] adjusting the width of QWs or barriers [ 25,26 ] ; Besides, many proposals for optimizing QW structure have been reported: triangular QWs, [ 27 ] staggered InGaN QWs, [ 28–31 ] gradually varying indium content QWs, [ 32 ] trapezoidal QWs, [ 33,34 ] step‐stage QWs, [ 35 ] zigzag‐shaped QWs, [ 36 ] and W‐shaped QWs. [ 37 ] This method uses a variety of ways for designing the energy band of QWs and barriers to ameliorate carrier transport and distribution as well as to obtain a marked advanced radiative recombination rate.…”

Innovative Stacked Yellow and Blue Mini-LED Chip for White Lamp Applications

“…One approach involves optimizing the substrate by inserting a stress buffer layer [ 18 ], which has shown promise in enhancing the optoelectronic properties and mitigating the QCSE [ 19 , 20 , 21 ]. Additionally, varying the thickness of the active layer [ 22 ] and employing staggered QW structures [ 21 , 23 , 24 , 25 ] can improve the overlap of hole and electron wavefunctions, leading to higher optical output power and electroluminescence intensity [ 25 ]. In a previous study, the introduction of a stress buffer layer significantly improved the external quantum efficiency (EQE) and mitigated QCSE phenomena in RGB LEDs.…”

Design and Simulation of InGaN-Based Red Vertical-Cavity Surface-Emitting Lasers

“…Interestingly, the staggered MQW structure design has recently been demonstrated in InGaN-based blue LEDs [ 45 ], green LEDs [ 46 ], and AlGaN-based deep UV lasers [ 47 ]. Additionally, the optoelectronic characteristics of InGaN-based green micro-resonant cavity light-emitting diodes (µ-RCLEDs), which consist of a three-layer staggered InGaN MQWs, bottom nanoporous n-GaN DBRs, and top Ta 2 O 5 /SiO 2 DBRs, have been numerically investigated [ 48 ].…”