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International Journal of Photoenergy
Volume 2014, Article ID 621789, 8 pages
http://dx.doi.org/10.1155/2014/621789
Research Article

Void Shapes Controlled by Using Interruption-Free Epitaxial Lateral Overgrowth of GaN Films on Patterned SiO2 AlN/Sapphire Template

Institute of Lighting and Energy Photonics, National Chiao Tung University, Tainan 71150, Taiwan

Received 20 February 2014; Revised 26 April 2014; Accepted 2 June 2014; Published 18 June 2014

Academic Editor: Nelson Tansu

Copyright © 2014 Yu-An Chen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

GaN epitaxial layers with embedded air voids grown on patterned SiO2 AlN/sapphire templates were proposed. Using interruption-free epitaxial lateral overgrowth technology, we realized uninterrupted growth and controlled the shape of embedded air voids. These layers showed improved crystal quality using X-ray diffraction and measurement of etching pits density. Compared with conventional undoped-GaN film, the full width at half-maximum of the GaN (002) and (102) peaks decreased from 485 arcsec to 376 arcsec and from 600 arcsec to 322 arcsec, respectively. Transmission electron microscopy results showed that the coalesced GaN growth led to bending threading dislocation. We also proposed a growth model based on results of scanning electron microscopy.