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Back Cover: Investigation of Ni/Ag contact to p‐GaN with an O 2 plasma treatment and its application to GaN‐based LEDs (Phys. Status Solidi A 8/2012)
Author(s) -
Lin NanMing,
Shei ShihChang,
Chang ShoouJinn
Publication year - 2012
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201290020
Subject(s) - materials science , light emitting diode , optoelectronics , current crowding , plasma , diode , schottky barrier , thermionic emission , opacity , indium tin oxide , indium , layer (electronics) , current (fluid) , oxide , electrode , wide bandgap semiconductor , optics , nanotechnology , electron , chemistry , metallurgy , electrical engineering , physics , quantum mechanics , engineering
Current spreading is an important issue for GaN‐based light emitting diodes (LEDs) because the hole concentration in p‐GaN is low in general. Even with a transparent current spreading layer, such as indium tin oxide, the current crowding still occurs. Therefore, the photons generated in the active region will be partially absorbed by an opaque p‐pad electrode and then cause the decrease of light extraction efficiency. Lin, Shei, and Chang (pp. 1568–1574 ) investigate the formation of a Schottky contact at the interface of Ni‐Ag/p‐GaN with an O 2 plasma treatment and demonstrate the excellent performance of LEDs with Ni/Ag contact to p‐GaN through the O 2 plasma treatment. The dominant transport mechanism of the Ni‐Ag/p‐GaN structure changes from thermionic emission to field emission when increasing the O 2 plasma treatment time from 1 min to 5 min. The larger output power should be attributed to best current spreading and a high reflectance of the Ni/Ag mirror.