Open AccessHigh-power and reliable GaN-based vertical light-emitting diodes on 4-inch silicon substrate
Author(s) -
Shengjun Zhou,
Haohao Xu,
Bin Tang,
Yingce Liu,
Hui Wan,
Jiahao Miao
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.0a1506
Subject(s) - light emitting diode , materials science , optoelectronics , current crowding , diode , substrate (aquarium) , etching (microfabrication) , silicon , current density , optics , layer (electronics) , nanotechnology , oceanography , physics , quantum mechanics , geology
High-power and reliable GaN-based vertical light-emitting diodes (V-LEDs) on 4-inch silicon substrate were fabricated and characterized in this article. The metallization scheme reliability was improved by depositing the Pt/Ti films that surround the compressed Ag/TiW films to protect it from environmental humidity. We demonstrated that although current crowding in V-LEDs was not as severe as that in lateral light-emitting diodes (L-LEDs), high current density around the opaque metal n-electrode in V-LEDs remained a problem. A SiO 2 current blocking layer (CBL) was incorporated in V-LEDs to modify the current distribution. Roughening the emitting surface of V-LEDs with KOH and H 3 PO 4 etchant was compared and the influence of surface roughening on the emission property of V-LEDs was studied. The high-power V-LEDs showed low forward voltage with small series resistance and high light output power (LOP) without saturation up to 1300 mA. Under 350 mA injection current, V-LEDs achieved an excellent light output power (LOP) of 501 mW with the peak emission wavelength at 453 nm. The prominent output performance of V-LEDs demonstrated in this work confirmed that integrating the optimized metallization scheme, SiO 2 CBL and surface texturing by KOH wet etching is an effective approach to higher performance V-LEDs.