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Title: Polarity dependence of the electrical characteristics of Ag reflectors for high-power GaN-based light emitting diodes

We report on the polarity dependence of the electrical properties of Ag reflectors for high-power GaN-based light-emitting diodes. The (0001) c-plane samples become ohmic after annealing in air. However, the (11–22) semi-polar samples are non-ohmic after annealing, although the 300 °C-annealed sample shows the lowest contact resistivity. The X-ray photoemission spectroscopy (XPS) results show that the Ga 2p core level for the c-plane samples experiences larger shift toward the valence band than that for the semi-polar samples. The XPS depth profile results show that unlike the c-plane samples, the semi-polar samples contain some amounts of oxygen at the Ag/GaN interface regions. The outdiffusion of Ga atoms is far more significant in the c-plane samples than in the semi-polar samples, whereas the outdiffusion of N atoms is relatively less significant in the c-plane samples. On the basis of the electrical and XPS results, the polarity dependence of the electrical properties is described and discussed.
Authors:
;  [1] ;  [2] ;  [3]
  1. Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of)
  2. Department of LED Business, Chip Development Group, LG Innotek, Paju 413-901 (Korea, Republic of)
  3. School of Applied Chemical Engineering, Chonnam National University, Gwangju 500-757 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22267725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 17; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANNEALING; ELECTRICAL PROPERTIES; GALLIUM NITRIDES; LIGHT EMITTING DIODES; PHOTOEMISSION; X-RAY PHOTOELECTRON SPECTROSCOPY