Optoelectronic Simulations of InGaN-Based Green Micro-Resonant Cavity Light-Emitting Diodes with Staggered Multiple Quantum Wells

Abstract

In this research, we compared the performance of commercial μ-LEDs and three-layered staggered QW μ-LED arrays. We also investigated the self-heating effect. We proposed a green micro-resonant cavity light-emitting diode (µ-RCLED) that consists of a three-layer staggered InGaN with multiple quantum wells (MQWs), a bottom layer of nanoporous n-GaN distributed Bragg reflectors (DBRs), and a top layer of Ta2O5/SiO2 DBRs. We systematically performed simulations of the proposed µ-RCLEDs. For the InGaN MQWs with an input current of 300 mA, the calculated wavefunction overlaps are 8.8% and 18.1% for the regular and staggered structures, respectively. Furthermore, the staggered MQWs can reduce the blue-shift of electroluminescence from 10.25 nm, obtained with regular MQWs, to 2.25 nm. Due to less blue-shift, the output power can be maintained even at a high input current. Conversely, by employing 6.5 pairs of Ta2O5/SiO2 DBRs stacks, the full width at half maximum (FWHM) can be significantly reduced from 40 nm, obtained with ordinary µ-LEDs, to 0.3 nm, and a divergence angle smaller than 60° can be obtained. Our simulation results suggest that the µ-RCLEDs can effectively resolve the wavelength instability and color purity issues of conventional µ-LEDs.

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

“…In addition, the emission peak wavelengths and corresponding full width at half maximum of these two InGaN MQW designs for each current density are methodically listed in Figure 4b,d. Drawing from previous studies [47,48] and our simulation results, we observe that the calculated emission peak wavelength of the regular InGaN MQW design shifts from 615.24 nm to 601.02 nm, resulting in a blue shift of 14.22 nm, and the calculated FWHM increases from 41.43 nm to 47.36 nm. Conversely, for the staggered InGaN MQW design, the emission peak wavelength and FWHM will shift from 615.62 nm to 610.18 nm and 40.72 nm to 45.76 nm, respectively.…”

“…When the emission wavelength of the InGaN MQW aligns with the laser mode wavelength of the Fabry–Pérot (F-P) like cavity, the light output efficiency can be significantly enhanced, and the FWHM can be greatly reduced. These predictions were based on the findings of a previous study on green µ-RCLED [ 48 ].…”

“…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 ]. However, no literature has discussed the design of InGaN-based red vertical-cavity surface-emitting lasers using staggered MQWs, nanoporous DBRs, and high-index contrast grating mirrors.…”

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.…”

Ameliorating Uniformity and Color Conversion Efficiency in Quantum Dot-Based Micro-LED Displays through Blue–UV Hybrid Structures

“…In the absence of a protective layer, QDs undergo rapid quenching, leading to a substantial decline in photoluminescence quantum yield (PLQY). Therefore, incorporating a passivation protection layer is crucial for CCLs [ 21 ]. Lee et al employed atomic layer deposition (ALD) passivation techniques to coat the QD surface with Al 2 O 3 , demonstrating impressive reliability in long-term aging and high temperature and humidity tests [ 22 ].…”