Numerical simulations of light‐extraction efficiencies of light‐emitting diodes on micro and nanopatterned sapphire substrates

Cui, Hao; Park, Si-Hyun

doi:10.1049/mnl.2014.0373

Cited by 8 publications

(5 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…8 Flip-chip (FC)-LEDs are becoming increasingly popular as a means to facilitate chip-level integration and achieve high power and efficiency. [9][10][11] For example, in FC-LEDs, heat can dissipate through the Si submount, and the light output power will not be influenced by this because of optical blocking by the highly reflective electrodes.…”

Section: Introductionmentioning

confidence: 99%

Improved light extraction efficiency of GaN-based flip-chip light-emitting diodes with an antireflective interface layer

Dongxue

Liu

et al. 2016

AIP Advances

View full text Add to dashboard Cite

GaN-based flip-chip light-emitting diodes (FC-LEDs) grown on nanopatterned sapphire substrates (NPSS) are fabricated using self-assembled SiO2 nanospheres as masks during inductively coupled plasma etching. By controlling the pattern spacing, epitaxial GaN can be grown from the top or bottom of patterns to obtain two different GaN/substrate interfaces. The optoelectronic characteristics of FC-LED chips with different GaN/sapphire interfaces are studied. The FC-LED with an antireflective interface layer consisting of a NPSS with GaN in the pattern spacings demonstrates better optical properties than the FC-LED with an interface embedded with air voids. Our study indicates that the two types of FC-LEDs grown on NPSS show higher crystal quality and improved electrical and optical characteristics compared with those of FC-LEDs grown on conventional planar sapphire substrates.

show abstract

Section: Introductionmentioning

confidence: 99%

Improved light extraction efficiency of GaN-based flip-chip light-emitting diodes with an antireflective interface layer

Dongxue

Liu

et al. 2016

AIP Advances

View full text Add to dashboard Cite

show abstract

“…121 It is worth noting that the ray-tracing method is an approximate theory, which will lose accuracy when structural size of patterns on PSS is smaller than the wavelength or even reaches the nano scale. 122 The FDTD method is based on wave optics, which directly divides the space with fine mesh for solving Maxwell's equations to investigate the wave propagation. 123 This method can be used for calculation involving subwavelength structures with complex shape.…”

Section: Lee Enhancement By Pssmentioning

confidence: 99%

Application of patterned sapphire substrate for III-nitride light-emitting diodes

Zhou

Zhao

et al. 2022

Nanoscale

View full text Add to dashboard Cite

show abstract

“…In addition, according to what I have learnt, all reported design principles related to ODR are based on flip-chip LED on flat sapphire substrate (FSS). But nowadays, patterned sapphire substrate (PSS) has been employed in the commercial high-brightness LEDs because it can improve light extraction efficiency [20]- [22] and epitaxial crystal quality [2], [23]. So it is also worth to investigate if the quarter-wave thick low-index dielectric layer in ODR is optimum for flip-chip LED on PSS.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Sapphire Substrates on Omni-Directional Reflector Design for Flip-Chip Near-Ultraviolet Light-Emitting Diodes

Zhang

Zheng

et al. 2019

IEEE Photonics J.

View full text Add to dashboard Cite

In this paper, we investigate the effect of omni-directional reflectors (ODRs) on the light extraction efficiency (LEE) for flip-chip near-ultraviolet light-emitting diodes (LEDs) on patterned (PSS) and flat sapphire substrate (FSS) using three-dimensional finite-difference time-domain method. Different design principles of ODR for the flip-chip LEDs on PSS and FSS are proposed to attain optimum LEE. For the flip-chip LED on FSS, the LEE curve is oscillatory with changing the thickness of the SiO 2 layer as a result of the coherent interference in the ODR and the optical cavity tuning effect for light source. Therefore, the thickness of the p-GaN needs to satisfy even times of quarter wave and the thickness of SiO 2 needs to be quarter wave. However, for the flip-chip LED on PSS, both the total internal reflection and the surface plasmon polariton resonance absorption play a major role leading to LEE increasing as the thickness of SiO 2 layer increases. As a result, SiO 2 layer with a thickness of over one wavelength is better, because the energy of evanescent wave decays to sufficiently negligible when it reaches the Al metal.

show abstract

Numerical simulations of light‐extraction efficiencies of light‐emitting diodes on micro and nanopatterned sapphire substrates

Cited by 8 publications

References 30 publications

Improved light extraction efficiency of GaN-based flip-chip light-emitting diodes with an antireflective interface layer

Improved light extraction efficiency of GaN-based flip-chip light-emitting diodes with an antireflective interface layer

Application of patterned sapphire substrate for III-nitride light-emitting diodes

The Effect of Sapphire Substrates on Omni-Directional Reflector Design for Flip-Chip Near-Ultraviolet Light-Emitting Diodes

Contact Info

Product

Resources

About