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 journalArticlepeer-review

    13 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

    Bibliographical note

    Funding Information:
    This work was supported by the industrial technology development program funded by the Ministry of Knowledge Economy (MKE), Korea and the industrial strategic technology development program, 10041878, development of WPE 75% LED device process and standard evaluation technology funded by the MKE, Korea.

    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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