Electrical characteristics of In/ITO p-type ohmic contacts for high-performance GaN-based light-emitting diodes

Joon Ho Oh, Kyoung Kook Kim, Hyun Gi Hong, Kyeong Jae Byeon, Heon Lee, Sang Won Yoon, Jae Pyoung Ahn, Tae Yeon Seong

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


We have investigated the annealing-induced improved electrical properties of In(10 nm)/ITO(200 nm) contacts with p-type GaN. The contacts become ohmic with a specific contact resistance of 2.75×103 Ω cm 2 upon annealing at 650 °C in air. X-ray photoemission spectroscopy (XPS) Ga 2p core levels obtained from the interface regions before and after annealing indicate a large band-bending of p-GaN, resulting in an increase in the Schottky barrier height. STEM/energy dispersive X-ray (EDX) profiling results exhibit the formation of interfacial In-Ga-Sn-oxide. Based on the STEM and XPS results, the ohmic formation mechanisms are described and discussed. It is also shown that patterning by nano-imprint lithography improves the light output power of blue LEDs by 1828% as compared to that of LEDs fabricated with unpatterned In/ITO contacts.

Original languageEnglish
Pages (from-to)272-275
Number of pages4
JournalMaterials Science in Semiconductor Processing
Issue number4
Publication statusPublished - 2010 Dec

Bibliographical note

Funding Information:
This work was supported by the Korea Research Foundation Grant funded by the Korean Government ( KRF-2008-313-D00593 ), the National Research Foundation grant through World Class University program ( R33-2008-000-10025-0 ) and the ERC Program ( 2009-0064868 ).


  • ITO
  • Light-emitting diode
  • Ohmic contact
  • Transparent electrode

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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