title: Spatially resolved and orientation dependent Raman mapping of epitaxial lateral overgrowth nonpolar a-plane GaN on r-plane sapphire.
abstract: Uncoalesced a-plane GaN epitaxial lateral overgrowth (ELO) structures have been synthesized along two mask stripe orientations on a-plane GaN template by MOCVD. The morphology of two ELO GaN structures is performed by Scanning electronic microscopy. The anisotropy of crystalline quality and stress are investigated by micro-Raman spectroscopy. According to the Raman mapping spectra, the variations on the intensity, peak shift and the full width at half maximum (FWHM) of GaN E2 (high) peak indicate that the crystalline quality improvement occurs in the window region of the GaN stripes along [0001], which is caused by the dislocations bending towards the sidewalls. Conversely, the wing regions have better quality with less stress as the dislocations propagated upwards when the GaN stripes are along []. Spatial cathodoluminescence mapping results further support the explanation for the different dislocation growth mechanisms in the ELO processes with two different mask stripe orientations.
authors.affiliation: Wide Bandap Semiconductor Technology Disciplines State Key Laboratory, School of Microelectronics, Xidian University, Xi'an 710071, China.
authors.forename: Teng
authors.initials: T
authors.lastname: Jiang
authors.affiliation: Wide Bandap Semiconductor Technology Disciplines State Key Laboratory, School of Microelectronics, Xidian University, Xi'an 710071, China.
authors.forename: Sheng-Rui
authors.initials: SR
authors.lastname: Xu
authors.affiliation: Wide Bandap Semiconductor Technology Disciplines State Key Laboratory, School of Microelectronics, Xidian University, Xi'an 710071, China.
authors.forename: Jin-Cheng
authors.initials: JC
authors.lastname: Zhang
authors.affiliation: School of Advanced Materials and Nanotechnology, Xidian University, Xi'an 710071, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Wide Bandap Semiconductor Technology Disciplines State Key Laboratory, School of Microelectronics, Xidian University, Xi'an 710071, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Hao
references.citation: Nature. 2000 Aug 24;406(6798):865-8
references.pmid: 10972282
references.citation: J Electron Microsc (Tokyo). 2000;49(2):323-30
references.pmid: 11108055
references.citation: Opt Express. 2007 Jul 23;15(15):9357-65
references.pmid: 19547278
references.citation: Nano Lett. 2013 Aug 14;13(8):3654-7
references.pmid: 23899164