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