Open AccessInGaN light-emitting diodes with oblique sidewall facets formed by selective growth on SiO_2 patterned GaN film
Author(s) -
Jinn-Kong Sheu,
KaoShuo Chang,
Shang Ju Tu,
Ming Lun Lee,
ChaoChin Yang,
Che Kang Hsu,
Wei Chih Lai
Publication year - 2010
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.18.00a562
Subject(s) - materials science , light emitting diode , optoelectronics , layer (electronics) , diode , sapphire , etching (microfabrication) , ohmic contact , optics , nanotechnology , laser , physics
In this study, GaN-based light-emitting diodes (LEDs) with naturally formed oblique sidewall facets (OSFs) were fabricated through a selective regrowth process. The SiO₂ mask layer was patterned on a heavily doped n-GaN template layer rather than on a sapphire substrate. As a result, the periphery of the LED included several OSFs around the regrown GaN mesa. While processing the device, dry etching was unnecessary for exposing the n-GaN underlying layer in order to form the n-type Ohmic contacts. This could be attributed to the fact that the n-GaN template layer with an electron concentration of around 8 × 10¹⁸/cm³ was exposed after the removal of the SiO₂ mask layer. With an injection current of 20 mA, GaN-based LEDs with OSFs exhibited a 21% enhancement in light output compared with those that have vertical sidewall facets. The enhancement is attributed to the fact that photons extracted from OSFs can reduce internal absorption loss.