Journal of Materials Research

Articles

Threading defect elimination in GaN nanowires

Stephen D. Herseea1 c1, Ashwin K. Rishinaramangalama1, Michael N. Fairchilda1, Lei Zhanga2 and Petros Varangisa2

a1 Center for High Technology Materials, University of New Mexico, Albuquerque, New Mexico 87106

a2 Nanocrystal Corporation, Albuquerque, New Mexico 87124

Abstract

This study describes the elimination of threading dislocations (TDs) in GaN nanostructures. Cross-sectional transmission electron microscopy (XTEM) analysis reveals that the nominal [0001] line direction of a TD changes when it enters a GaN nanostructure and the dislocation then terminates at a sidewall facet. It is suggested that the driving force for this process is the reduction of dislocation line energy, and for a pure-edge dislocation, this TD elimination process can be accomplished simply by dislocation climb. This mechanism is active whenever a threading defect is in close proximity to a surface. Preliminary XTEM analysis of defects in AlGaN and InGaN core–shell growth onto GaN nanostructures is also shown. Although more work is required to improve the quality of core–shell InGaN epitaxial growth, nanostructures appear to offer a route to defect-free, nonpolar GaN-based devices.

(Received January 26 2011)

(Accepted March 31 2011)

Key Words:

  • Dislocations;
  • Nanostructure;
  • Transmission electron microscopy

Correspondence:

c1 Address all correspondence to this author. e-mail: shersee@chtm.unm.edu

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