Strain distribution in GaN hexagons measured by Raman spectroscopy

Citation
R. Seitz et al., Strain distribution in GaN hexagons measured by Raman spectroscopy, PHYS ST S-B, 216(1), 1999, pp. 775-778
Citations number
8
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
PHYSICA STATUS SOLIDI B-BASIC RESEARCH
ISSN journal
0370-1972 → ACNP
Volume
216
Issue
1
Year of publication
1999
Pages
775 - 778
Database
ISI
SICI code
0370-1972(199911)216:1<775:SDIGHM>2.0.ZU;2-M
Abstract
Epitaxial growth of GaN layers normally starts in a three-dimensional growt h mode at nucleation sites. Growth islands are formed which coalesce when a certain layer thickness is achieved; In our samples these islands show hex agonal structure and in some cases a flat surface plane perpendicular to th e (0001) growth direction. We studied these hexagons by spatially resolved Raman spectroscopy. Raman spectroscopy is a powerful tool to determine stra in in GaN layers, because the E-2 Raman modes are very sensitive to the cha nge of the elastic properties of the material. In all cases we found that t he centre of the hexagons is nearly strain free whereas at the edges there is a tensile strain. This tensile strain, however, is not as high as in the surrounding film.