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Title: Growth and characterizations of GaN micro-rods on graphene films for flexible light emitting diodes

We report the growth of GaN micro-rods and coaxial quantum-well heterostructures on graphene films, together with structural and optical characterization, for applications in flexible optical devices. Graphene films were grown on Cu foil by means of chemical vapor deposition, and used as the substrates for the growth of the GaN micro-rods, which were subsequently transferred onto SiO{sub 2}/Si substrates. Highly Si-doped, n-type GaN micro-rods were grown on the graphene films using metal–organic chemical vapor deposition. The growth and vertical alignment of the GaN micro-rods, which is a critical factor for the fabrication of high-performance light-emitting diodes (LEDs), were characterized using electron microscopy and X-ray diffraction. The GaN micro-rods exhibited promising photoluminescence characteristics for optoelectronic device applications, including room-temperature stimulated emission. To fabricate flexible LEDs, In{sub x}Ga{sub 1–x}N/GaN multiple quantum wells and a p-type GaN layer were deposited coaxially on the GaN micro-rods, and transferred onto Ag-coated polymer substrates using lift-off. Ti/Au and Ni/Au metal layers were formed to provide electrical contacts to the n-type and p-type GaN regions, respectively. The micro-rod LEDs exhibited intense emission of visible light, even after transfer onto the flexible polymer substrate, and reliable operation was achieved following numerous cycles of mechanical deformation.
Authors:
; ; ; ;  [1] ; ;  [2]
  1. Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 151-747 (Korea, Republic of)
  2. Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22303566
Resource Type:
Journal Article
Resource Relation:
Journal Name: APL Materials; Journal Volume: 2; Journal Issue: 9; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; CHEMICAL VAPOR DEPOSITION; DEPOSITS; DOPED MATERIALS; ELECTRIC CONTACTS; ELECTRON MICROSCOPY; GALLIUM NITRIDES; GRAPHENE; LIGHT EMITTING DIODES; PHOTOLUMINESCENCE; POLYMERS; QUANTUM WELLS; SILICON OXIDES; STIMULATED EMISSION; SUBSTRATES; X-RAY DIFFRACTION