Highly thermally stable Pd/Zn/Ag ohmic contact to Ga-face p-type GaN

Dae Hyun Kim, Weon Cheol Lim, Jae Seong Park, Tae Yeon Seong

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Pd/Zn/Ag ohmic contacts to Ga-face p-type GaN were investigated as a function of annealing temperature. The Pd/Zn/Ag ohmic contacts exhibited a reflectance of 85% at 450 nm, which is higher than that of Ag-only contacts (57%) after annealing at 500 C. The alleviated agglomeration of the Pd/Zn/Ag ohmic contact due to the formation of ZnO at the surface seems to be responsible for the higher reflectance. The specific contact resistances of Ag-only and Pd/Zn/Ag contacts annealed at 500 C were 2.4 × 10-4 and 6.1 × 10-5 Ω cm2, respectively. GaN-based light-emitting diodes (LEDs) fabricated with the Pd/Zn/Ag contacts exhibited ∼20% higher output power at 20 mA than the LEDs fabricated with the Ag-only contacts annealed at 500 C. On the basis of X-ray photoemission spectroscopy and SEM results, the improved electrical and thermal properties are described.

Original languageEnglish
Pages (from-to)327-331
Number of pages5
JournalJournal of Alloys and Compounds
Volume588
DOIs
Publication statusPublished - 2014 Mar 5

Keywords

  • Electrode materials
  • Light absorption and reflection
  • Metals and alloys
  • Optical properties
  • Surfaces and interfaces

ASJC Scopus subject areas

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

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