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 language | English |
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Pages (from-to) | 327-331 |
Number of pages | 5 |
Journal | Journal of Alloys and Compounds |
Volume | 588 |
DOIs | |
Publication status | Published - 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