Open AccessInGaN/GaN nanowires grown on SiO_2 and light emitting diodes with low turn on voltages
Author(s) -
Youngseo Park,
Shafat Jahangir,
Yongjun Park,
P. Bhattacharya,
Junseok Heo
Publication year - 2015
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.23.00a650
Subject(s) - nanowire , materials science , optoelectronics , electroluminescence , molecular beam epitaxy , photoluminescence , epitaxy , diode , light emitting diode , transmission electron microscopy , indium gallium nitride , heterojunction , gallium nitride , amorphous solid , scanning electron microscope , layer (electronics) , optics , nanotechnology , crystallography , chemistry , physics , composite material
GaN nanowires and InGaN disk heterostructures are grown on an amorphous SiO 2 layer by a plasma-assisted molecular beam epitaxy. Structural studies using scanning electron microscopy and high-resolution transmission electron microscopy reveal that the nanowires grow vertically without any extended defect similarly to nanowires grown on Si. The as-grown nanowires have an intermediate region consisting of Ga, O, and Si rather than SiNx at the interface between the nanowires and SiO 2 . The measured photoluminescence shows a variation of peak wavelengths ranging from 580 nm to 635 nm because of non-uniform indium incorporation. The nanowires grown on SiO 2 are successfully transferred to a flexible polyimide sheet by Au-welding and epitaxial lift-off processes. The light-emitting diodes fabricated with the transferred nanowires are characterized by a turn-on voltage of approximately 4 V. The smaller turn-on voltage in contrast to those of conventional nanowire light-emitting diodes is due to the absence of an intermediate layer, which is removed during an epitaxial lift-off process. The measured electroluminescence shows peak wavelengths of 610-616 nm with linewidths of 116-123 nm.