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Title: Structural and electronic properties of GaN nanowires with embedded In{sub x}Ga{sub 1−x}N nanodisks

In the present study, the effects of various types of strain and indium concentration on the total energy and optoelectronic properties of GaN nanowires (NWs) with embedded In{sub x}Ga{sub 1−x}N nanodisks (NDs) are examined. In particular, the bi-axial, hydrostatic, and uniaxial strain states of the embedded In{sub x}Ga{sub 1−x}N NDs are investigated for multiple In concentrations. Density functional theory is employed to calculate the band structure of the NWs. The theoretical analysis finds that the supercell-size-dependent characteristics calculated for our 972-atom NW models are very close to the infinite supercell-size limit. It is established that the embedded In{sub x}Ga{sub 1−x}N NDs do not induce deep states in the band gap of the NWs. A bowing parameter of 1.82 eV is derived from our analysis in the quadratic Vegard's formula for the band gaps at the various In concentrations of the investigated In{sub x}Ga{sub 1−x}N NDs in GaN NW structures. It is concluded that up to ∼10% of In, the hydrostatic strain state is competitive with the bi-axial due to the radial absorption of the strain on the surfaces. Above this value, the dominant strain state is the bi-axial one. Thus, hydrostatic and bi-axial strain components coexist in the embedded NDs, andmore » they are of different physical origin. The bi-axial strain comes from growth on lattice mismatched substrates, while the hydrostatic strain originates from the lateral relaxation of the surfaces.« less
Authors:
; ; ; ;  [1] ; ;  [2] ;  [3] ;  [4]
  1. Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece)
  2. Department of Chemistry, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)
  3. School of Electrical and Electronic Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom)
  4. Institute of Experimental Physics I, Justus-Liebig-University Giessen, D-35392 Giessen (Germany)
Publication Date:
OSTI Identifier:
22490794
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION; CRYSTAL DEFECTS; DENSITY FUNCTIONAL METHOD; GALLIUM NITRIDES; NANOWIRES; RELAXATION; STRAINS; SUBSTRATES; SURFACES