Nature of luminescence and strain in gallium nitride nanowires

• Published in: Journal of crystal growth Vol. 311; no. 10; pp. 2982 - 2986
• Main Authors: Mastro, M.A., Maximenko, S., Gowda, M., Simpkins, B.S., Pehrsson, P.E., Long, J.P., Makinen, A.J., Freitas, J.A., Hite, J.K., Eddy, C.R., Kim, J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.05.2009; Elsevier
• Subjects: A1. Stresses; B1. Gallium compounds; B1. Nanomaterials; B2. Semiconducting gallium compounds; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Nanoscale materials and structures: fabrication and characterization; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Other luminescence and radiative recombination; Other topics in nanoscale materials and structures; Physics; Quantum wires; 81.07.Bc; B2. Semiconducting gallium compounds; A1. Stresses; B1. Nanomaterials; 81.15.Gh; B1. Gallium compounds; 81.05.Ea; Stresses; Semiconducting gallium compounds; Luminescence; Nanomaterials; Gallium nitride; III-V compound; B1; A1; B2; Optical properties; Size effect; Stress effects; Nanowires; Gallium compounds; Formation mechanism; Nanostructured materials; Defect formation; III-V semiconductors
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2009.01.053

Photo- and cathodo-luminescence measurements of a variable-diameter ensemble of GaN nanowires revealed a diameter-dependent, spectral emission distribution between 350 nm and 850 nm. Spectral analysis indicated that wires with a diameter less than 400 nm were dominated by a yellow luminescence with a weaker near UV/violet emission also present. Examination of this ensemble showed that there was a general trend in the ratio of near-UV-to-yellow emission intensities with increasing nanowire diameter. Additionally, a broad green emission appears in the nanowires with a diameter above approximately 200 nm. A calculation based on the nanoheteroepitaxy model indicates that this diameter represents a transitional thickness where strain is relieved by defect formation mechanisms with a characteristic green emission.