GaN-based semiconductors are of great technological importance for the fabrication of optoelectronic devices, such as light-emitting diodes (LEDs) and laser diodes. The further improvement of LED performance can be achieved through the enhancement of external quantum efficiency. In this regard, highquality p-type ohmic electrodes having low contact resistance and high transmittance (or reflectivity), along with thermal stability, must be developed because p-type ohmic contacts play a key role in the performance of LEDs. In this paper, we review recent advances in p-type ohmic-contact technology for GaN-based LEDs. A variety of methods for forming transparent and reflective ohmic contacts are introduced.
Bibliographical noteFunding Information:
Manuscript received June 2, 2009; revised September 15, 2009. First published December 1, 2009; current version published December 23, 2009. This work was supported in part by the Ministry of Knowledge and Economy through the Manpower Development Program for Energy and Resources under Grant 2008-E-AP-HM-P-16-0000, by the Korean government under Korea Research Foundation Grant KRF-2008-313-D00593, and by the Ministry of Education Science and Technology through World Class University Program under Grant R33-2008-000-10025-0. The review of this paper was arranged by Editor M. J. Kumar.
- Gallium nitride
- Light-emitting diodes (LEDs)
- Transparent and reflective ohmic contacts
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering