Light Extraction Enhancement of GaN-Based Light-Emitting Diodes with Textured Sidewalls and ICP-Transferred Nanohemispherical Backside Reflector

Chun Yen Chen, Wen-Chau Liu

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Textured-sidewall GaN-based light-emitting diodes (LEDs) with convex and 45° patterns and an inductively coupled plasma (ICP)-transferred nanohemispherical backside reflector, formed using an ICP etching process, are fabricated and studied. For devices with textured sidewalls, the scattering probability of photons at the GaN/air interface is increased and the light extraction efficiency is enhanced since photons are allowed to find escape cones in the horizontal direction. With the ICP-transferred nanohemispherical backside reflector, reflected photons can be easily scattered and redirected in arbitrary directions for light extraction and thus have more opportunities to escape the devices. The LED with 45° sidewalls and a backside reflector exhibited the significant improvements of 55.8%, 49.3%, 47.2%, and 55.4% in light output power, luminous flux, external quantum efficiency, and wall-plug efficiency, respectively, compared to those of a conventional LED without these specific designs (Device A). In addition, the higher intensities in a light emission mapping image and improved far-field patterns are obtained for the studied device. The enhanced optical performance is mainly attributed to the increased light extraction in all directions due to a significant reduction in the total internal reflection by the textured sidewalls and a backside reflector. Therefore, textured-sidewall structures and an ICP-transferred nanohemispherical backside reflector are promising for high-power GaN-based LED applications.

Original languageEnglish
Article number7974814
Pages (from-to)3672-3677
Number of pages6
JournalIEEE Transactions on Electron Devices
Volume64
Issue number9
DOIs
Publication statusPublished - 2017 Sep 1

Fingerprint

Inductively coupled plasma
Light emitting diodes
Photons
Plasma etching
Light emission
Quantum efficiency
Cones
Scattering
Fluxes
Air
Direction compound

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

Cite this

@article{98addc895d63432a922a4964aa7727f9,
title = "Light Extraction Enhancement of GaN-Based Light-Emitting Diodes with Textured Sidewalls and ICP-Transferred Nanohemispherical Backside Reflector",
abstract = "Textured-sidewall GaN-based light-emitting diodes (LEDs) with convex and 45° patterns and an inductively coupled plasma (ICP)-transferred nanohemispherical backside reflector, formed using an ICP etching process, are fabricated and studied. For devices with textured sidewalls, the scattering probability of photons at the GaN/air interface is increased and the light extraction efficiency is enhanced since photons are allowed to find escape cones in the horizontal direction. With the ICP-transferred nanohemispherical backside reflector, reflected photons can be easily scattered and redirected in arbitrary directions for light extraction and thus have more opportunities to escape the devices. The LED with 45° sidewalls and a backside reflector exhibited the significant improvements of 55.8{\%}, 49.3{\%}, 47.2{\%}, and 55.4{\%} in light output power, luminous flux, external quantum efficiency, and wall-plug efficiency, respectively, compared to those of a conventional LED without these specific designs (Device A). In addition, the higher intensities in a light emission mapping image and improved far-field patterns are obtained for the studied device. The enhanced optical performance is mainly attributed to the increased light extraction in all directions due to a significant reduction in the total internal reflection by the textured sidewalls and a backside reflector. Therefore, textured-sidewall structures and an ICP-transferred nanohemispherical backside reflector are promising for high-power GaN-based LED applications.",
author = "Chen, {Chun Yen} and Wen-Chau Liu",
year = "2017",
month = "9",
day = "1",
doi = "10.1109/TED.2017.2720685",
language = "English",
volume = "64",
pages = "3672--3677",
journal = "IEEE Transactions on Electron Devices",
issn = "0018-9383",
publisher = "Institute of Electrical and Electronics Engineers Inc.",
number = "9",

}

TY - JOUR

T1 - Light Extraction Enhancement of GaN-Based Light-Emitting Diodes with Textured Sidewalls and ICP-Transferred Nanohemispherical Backside Reflector

AU - Chen, Chun Yen

AU - Liu, Wen-Chau

PY - 2017/9/1

Y1 - 2017/9/1

N2 - Textured-sidewall GaN-based light-emitting diodes (LEDs) with convex and 45° patterns and an inductively coupled plasma (ICP)-transferred nanohemispherical backside reflector, formed using an ICP etching process, are fabricated and studied. For devices with textured sidewalls, the scattering probability of photons at the GaN/air interface is increased and the light extraction efficiency is enhanced since photons are allowed to find escape cones in the horizontal direction. With the ICP-transferred nanohemispherical backside reflector, reflected photons can be easily scattered and redirected in arbitrary directions for light extraction and thus have more opportunities to escape the devices. The LED with 45° sidewalls and a backside reflector exhibited the significant improvements of 55.8%, 49.3%, 47.2%, and 55.4% in light output power, luminous flux, external quantum efficiency, and wall-plug efficiency, respectively, compared to those of a conventional LED without these specific designs (Device A). In addition, the higher intensities in a light emission mapping image and improved far-field patterns are obtained for the studied device. The enhanced optical performance is mainly attributed to the increased light extraction in all directions due to a significant reduction in the total internal reflection by the textured sidewalls and a backside reflector. Therefore, textured-sidewall structures and an ICP-transferred nanohemispherical backside reflector are promising for high-power GaN-based LED applications.

AB - Textured-sidewall GaN-based light-emitting diodes (LEDs) with convex and 45° patterns and an inductively coupled plasma (ICP)-transferred nanohemispherical backside reflector, formed using an ICP etching process, are fabricated and studied. For devices with textured sidewalls, the scattering probability of photons at the GaN/air interface is increased and the light extraction efficiency is enhanced since photons are allowed to find escape cones in the horizontal direction. With the ICP-transferred nanohemispherical backside reflector, reflected photons can be easily scattered and redirected in arbitrary directions for light extraction and thus have more opportunities to escape the devices. The LED with 45° sidewalls and a backside reflector exhibited the significant improvements of 55.8%, 49.3%, 47.2%, and 55.4% in light output power, luminous flux, external quantum efficiency, and wall-plug efficiency, respectively, compared to those of a conventional LED without these specific designs (Device A). In addition, the higher intensities in a light emission mapping image and improved far-field patterns are obtained for the studied device. The enhanced optical performance is mainly attributed to the increased light extraction in all directions due to a significant reduction in the total internal reflection by the textured sidewalls and a backside reflector. Therefore, textured-sidewall structures and an ICP-transferred nanohemispherical backside reflector are promising for high-power GaN-based LED applications.

UR - http://www.scopus.com/inward/record.url?scp=85023601015&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85023601015&partnerID=8YFLogxK

U2 - 10.1109/TED.2017.2720685

DO - 10.1109/TED.2017.2720685

M3 - Article

VL - 64

SP - 3672

EP - 3677

JO - IEEE Transactions on Electron Devices

JF - IEEE Transactions on Electron Devices

SN - 0018-9383

IS - 9

M1 - 7974814

ER -