Numerical simulation and experimental investigation of GaN-based flip-chip LEDs and top-emitting LEDs

Liu, Xingtong; Zhou, Shengjun; Gao, Yixin; Hu, Haiming; Liu, Yingce; Chen, Gui; Liu, Sheng

doi:10.1364/ao.56.009502

Cited by 20 publications

(13 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, metallic mirrors including Al and Ag suffer from inferior ohmic contact behavior and poor adhesion to the p -GaN layer. As an alternative to metallic reflector, the dielectric DBR has many advantages over a metallic reflector, such as low optical loss, high reflectance, and high mechanical robustness [45,46].…”

Section: Introductionmentioning

confidence: 99%

Effect of Dielectric Distributed Bragg Reflector on Electrical and Optical Properties of GaN-Based Flip-Chip Light-Emitting Diodes

Zhou

Liu

et al. 2018

Micromachines

Self Cite

View full text Add to dashboard Cite

We demonstrated two types of GaN-based flip-chip light-emitting diodes (FCLEDs) with distributed Bragg reflector (DBR) and without DBR to investigate the effect of dielectric TiO2/SiO2 DBR on optical and electrical characteristics of FCLEDs. The reflector consisting of two single TiO2/SiO2 DBR stacks optimized for different central wavelengths demonstrates a broader reflectance bandwidth and a less dependence of reflectance on the incident angle of light. As a result, the light output power (LOP) of FCLED with DBR shows 25.3% higher than that of FCLED without DBR at 150 mA. However, due to the better heat dissipation of FCLED without DBR, it was found that the light output saturation current shifted from 268 A/cm2 for FCLED with DBR to 296 A/cm2 for FCLED without DBR. We found that the use of via-hole-based n-type contacts can spread injection current uniformly over the entire active emitting region. Our study paves the way for application of DBR and via-hole-based n-type contact in high-efficiency FCLEDs.

show abstract

Section: Introductionmentioning

confidence: 99%

Effect of Dielectric Distributed Bragg Reflector on Electrical and Optical Properties of GaN-Based Flip-Chip Light-Emitting Diodes

Zhou

Liu

et al. 2018

Micromachines

Self Cite

View full text Add to dashboard Cite

show abstract

“…The growth rate are determined by the deposition speed calculated by the measured thickness of each layer using a step profiler and a broadband spectroscopic ellipsometer (EOPTICS ME-L). And optical constants about refractive index (n) and extinction coefficient (k) were simulated by anslysis software, which can be found in our previous report [18]. Table 1.…”

Section: Methodsmentioning

confidence: 99%

High Performance Wide Angle DBR Design for Optoelectronic Devices

et al. 2021

View full text Add to dashboard Cite

To improve the performance of optoelectronic devices, a high performance wide angle SiO2/Ti3O5 Distributed Bragg Reflector (DBR) mirror was designed and fabricated on double polished sapphire substrate. 17-pairs gradually varied DBR structure was applied in order to acquire a broad stopband reflectivity over 95% from 400nm to 800nm, covering the whole visible light region. The DBR mirrors deposited at the backside of optoelectronics devices are also demonstrated to remain a high reflectivity at wide incident angles, which improves the emission efficiency of LEDs and light absorption efficiency of InGaN/GaN photoelectrochemical cell (PEC).

show abstract

“…An electron‐blocking layer and highly conductive p‐ and n‐type‐doped AlGaN structures were introduced to increase the charge balance . In addition, flip‐chip (FC) LED structures have been employed owing to the excellent heat dissipation, large lifetime, and simple packaging …”

Section: Introductionmentioning

confidence: 99%

Smart Wide‐Bandgap Omnidirectional Reflector as an Effective Hole‐Injection Electrode for Deep‐UV Light‐Emitting Diodes

Lee

Park

Shin

et al. 2019

Advanced Optical Materials

View full text Add to dashboard Cite

Deep‐ultraviolet light‐emitting diodes (DUV‐LEDs) find widespread applications in various industries and are a focus area in environmental and life science research. However, the quantum efficiency of DUV‐LEDs is still low because of the unbalanced hole injection, high operation voltage, and low reflectivity of the p‐electrode. In this study, a smart wide‐bandgap omnidirectional reflector (ODR), which simultaneously acts as an effective hole‐injection electrode, is demonstrated for a flip‐chip DUV‐LED. The smart ODR is composed of p‐type AlGaN (p‐AlGaN)/Ni:AlN/Al with a high reflectivity of 94.2% at 280 nm, in which AlN with a theoretically calculated thickness of 40 nm is Ni‐doped using the pulsed electrical breakdown (PEBD) method. The smart ODR‐mounted AlGaN‐multiquantum‐well‐based DUV‐LED exhibits a remarkable wall‐plug efficiency (4.8%) and high external quantum efficiency (8.5%) at a low operation voltage of 9.75 V owing to the fused layer of Ni3N and Ga vacancies formed in the interfacial region of the p‐AlGaN and AlN layers, through the mutual diffusion of Ni and Ga during PEBD. The interface‐mediated Ohmic contact leads to an effective hole injection without reducing the reflectivity, yielding increased optical output and electric input powers. The proposed smart ODR can provide an innovative route for the manipulation of DUV light.

show abstract

Numerical simulation and experimental investigation of GaN-based flip-chip LEDs and top-emitting LEDs

Cited by 20 publications

References 36 publications

Effect of Dielectric Distributed Bragg Reflector on Electrical and Optical Properties of GaN-Based Flip-Chip Light-Emitting Diodes

Effect of Dielectric Distributed Bragg Reflector on Electrical and Optical Properties of GaN-Based Flip-Chip Light-Emitting Diodes

High Performance Wide Angle DBR Design for Optoelectronic Devices

Smart Wide‐Bandgap Omnidirectional Reflector as an Effective Hole‐Injection Electrode for Deep‐UV Light‐Emitting Diodes

Contact Info

Product

Resources

About