Glass-Based Transparent Conductive Electrode: Its Application to Visible-to-Ultraviolet Light-Emitting Diodes

Tae Ho Lee, Kyeong Heon Kim, Byeong Ryong Lee, Ju Hyun Park, E. Fred Schubert, Tae Geun Kim

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Nitride-based ultraviolet light-emitting diodes (UV LEDs) are promising replacements for conventional UV lamps. However, the external quantum efficiency of UV LEDs is much lower than for visible LEDs due to light absorption in the p-GaN contact and electrode layers, along with p-AlGaN growth and doping issues. To minimize such absorption, we should obtain direct ohmic contact to p-AlGaN using UV-transparent ohmic electrodes and not use p-GaN as a contact layer. Here, we propose a glass-based transparent conductive electrode (TCE) produced using electrical breakdown (EBD) of an AlN thin film, and we apply the thin film to four (Al)GaN-based visible and UV LEDs with thin buffer layers for current spreading and damage protection. Compared to LEDs with optimal ITO contacts, our LEDs with AlN TCEs exhibit a lower forward voltage, higher light output power, and brighter light emission for all samples. The ohmic transport mechanism for current injection and spreading from the metal electrode to p-(Al)GaN layer via AlN TCE is also investigated by analyzing the p-(Al)GaN surface before and after EBD.

Original languageEnglish
Pages (from-to)35668-35677
Number of pages10
JournalACS Applied Materials and Interfaces
Volume8
Issue number51
DOIs
Publication statusPublished - 2016 Dec 28

Keywords

  • conducting filament
  • light-emitting diode
  • transparent conductive electrode
  • ultraviolet
  • wide-bandgap

ASJC Scopus subject areas

  • Materials Science(all)

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