Fabrication of HfO2/TiO2–based conductive distributed Bragg reflectors: Its application to GaN-based near-ultraviolet micro-light-emitting diodes

Sang Hoon Oh, Tae Ho Lee, Kyung Rock Son, Tae Geun Kim

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Distributed Bragg reflector (DBR) has been used to enhance the performance of various optoelectronic devices because of its higher reflectance than metal reflector, particularly at a specific wavelength. However, the insulating property of the DBR structure have limited its use where the current injection is required (e.g., below electrodes). Here, we introduce a way to overcome this limit, by creating conductive paths in the DBR-electrode structure using an electrical breakdown process; thereby, achieving an ohmic contact with p-GaN contact layers, and finally apply to ultraviolet micro-light-emitting diodes (μLEDs) to verify the validity of the method. Specifically, by inserting three pairs of TiO2/HfO2-based conductive DBR structures under a Cr/Ni/Au-based p-type electrode, the reflectance of the p-type electrode was increased up to 95%, simultaneously increasing the output power of the μLED by 5% by reducing the light absorption at the p-type electrode by the reflection of light without electrical losses. This approach is expected to offer a great flexibility in the design of conventional devices using DBR structures.

Original languageEnglish
Pages (from-to)490-495
Number of pages6
JournalJournal of Alloys and Compounds
Volume773
DOIs
Publication statusPublished - 2019 Jan 30

Keywords

  • Distributed Bragg reflector
  • Electrical breakdown process
  • Light extraction efficiency
  • Light-emitting diodes
  • Ultraviolet

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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