Abstract
We report on the improved performance of near-ultraviolet (385 nm) InGaN/GaN multi-quantum well light emitting diodes (LEDs) by enhancing the thermal and electrical properties of Ag-based reflector. It is shown that after annealing at 500 °C, indium (In)-overlaid Ag contact exhibits considerably higher reflectivity at 385 nm than Ag only contact. After annealing at 500°C, both the Ag only and In-overlaid Ag contacts are ohmic with a specific contact resistance of 6.7 × 10-4 and 8.7 × 10-5 Ω cm2, respectively. Near-UV (385 nm) LEDs fabricated with annealed Ag only and In-overlaid Ag reflectors show a forward-bias voltage of 3.4 and 3.37 V at an injection current of 20 mA, respectively. The LEDs with the annealed In-overlaid Ag reflector exhibit 24.7% higher light output power (at 20 mA) than the LEDs with the 500°C-annealed Ag only reflector. X-ray photoemission spectroscopy was performed to understand the improved electrical properties of the In-overlaid Ag reflectors. The enhanced thermal stability of In-overlaid Ag reflector is also briefly described.
Original language | English |
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Pages (from-to) | 7-14 |
Number of pages | 8 |
Journal | Superlattices and Microstructures |
Volume | 64 |
DOIs | |
Publication status | Published - 2013 |
Bibliographical note
Funding Information:This work was supported by the World Class University program through the National Research Foundation of Korea funded by MEST ( R33-2008-000-10025-0 ), the Industrial Strategic Technology Development Program funded by MKE, Korea, and Development of WPE 75% LED Device Process and Standard Evaluation Technology funded by the MKE (Korea).
Keywords
- Ag ohmic reflector
- In overlayer
- Near-ultraviolet light-emitting diode
- Thermal stability
ASJC Scopus subject areas
- General Materials Science
- Condensed Matter Physics
- Electrical and Electronic Engineering