Improved device performance in nonpolar a -plane GaN LEDs using a Ni/Al/Ni/Au n-type ohmic contact

Dong Ho Kim, Su Jin Kim, Seung Hwan Kim, Tak Jeong, Sung Min Hwang, Tae Geun Kim

Research output: Contribution to journalArticle

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The authors report upon the increased light-output power (Pout) via a reduction in the forward voltage (Vf) for nonpolar a -plane GaN LEDs using Ni/Al/Ni/Au n-type ohmic contacts. The specific contact resistivity of the Ni/Al/Ni/Au contact is found to be as low as 5.6 × 10-5 whereas that of a typical Ti/Al/Ni/Au contact is 6.8 × 10-4 Ω cm2, after annealing at 700 °C. The X-ray photoelectron spectroscopy results show that the upward surface band bending is less pronounced for the Ni/Al contact compared to the Ti/Al contact, leading to a decrease in the effective Schottky barrier height (SBH). The Vf of the nonpolar LEDs decreases by 10% and Pout increases by 15% when the Ni/Al/Ni/Au scheme is used instead of the typical Ti/Al/Ni/Au metal scheme.

Original languageEnglish
Pages (from-to)274-276
Number of pages3
JournalPhysica Status Solidi - Rapid Research Letters
Issue number8
Publication statusPublished - 2011 Aug 1



  • Current injection
  • LED
  • Ni-Al alloys
  • Nonpolar GaN

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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