High electron mobility through the edge states in random networks of c-axis oriented wedge-shaped GaN nanowalls grown by molecular beam epitaxy

Journal Article · Mon Sep 24 04:00:00 EDT 2012 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4755775· OSTI ID:22080460

Bhasker, H P; Dhar, S; Sain, A ^[1]; Kesaria, Manoj; Shivaprasad, S M ^[2]

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1. Physics Department, Indian Institute of Technology Bombay, Powai, Mumbai 400076 (India)
2. International Centre for Material Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064 (India)

Transport and optical properties of random networks of c-axis oriented wedge-shaped GaN nanowalls grown spontaneously on c-plane sapphire substrates through molecular beam epitaxy are investigated. Our study suggests a one dimensional confinement of carriers at the top edges of these connected nanowalls, which results in a blue shift of the band edge luminescence, a reduction of the exciton-phonon coupling, and an enhancement of the exciton binding energy. Not only that, the yellow luminescence in these samples is found to be completely suppressed even at room temperature. All these changes are highly desirable for the enhancement of the luminescence efficiency of the material. More interestingly, the electron mobility through the network is found to be significantly higher than that is typically observed for GaN epitaxial films. This dramatic improvement is attributed to the transport of electrons through the edge states formed at the top edges of the nanowalls.

• OSTI ID: 22080460
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 13 Vol. 101; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
BINDING ENERGY
CONFINEMENT
COUPLING
ELECTRIC CONDUCTIVITY
ELECTRON MOBILITY
ELECTRONS
FILMS
GALLIUM NITRIDES
INTERACTIONS
LAYERS
MOLECULAR BEAM EPITAXY
NANOSTRUCTURES
OPTICAL PROPERTIES
PHOTOLUMINESCENCE
RANDOMNESS
SAPPHIRE
SEMICONDUCTOR MATERIALS
SUBSTRATES
TEMPERATURE RANGE 0273-0400 K