Premium
Surface topology caused by dislocations in polar, semipolar, and nonpolar InGaN/GaN heterostructures
Author(s) -
Schade L.,
Wernicke T.,
Raß J.,
Ploch S.,
Weyers M.,
Kneissl M.,
Schwarz U. T.
Publication year - 2014
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201300448
Subject(s) - hillock , heterojunction , materials science , perpendicular , cathodoluminescence , photoluminescence , optoelectronics , condensed matter physics , polar , quantum well , luminescence , optics , geometry , physics , composite material , laser , mathematics , astronomy
The impact of dislocations on surface topology as well as on quantum well emission in c ‐plane, semipolar, and nonpolar InGaN/GaN heterostructures is being analyzed by micro‐photoluminescence and white‐light‐interferometry. V‐pits with (10 1 ¯ 1) and (10 1 ¯4 ¯ ) side facets are identified in a (10 1 ¯ 2) semipolar heterostructure. Hillocks formed by spiral growth around screw dislocations change from hexagonal to triangular to rectangular shape in polar, semipolar, and nonpolar heterostructures, respectively, reflecting the symmetry of the individual surface. The emission in semipolar quantum wells, grown homoepitaxially on bulk GaN substrates, show dark stripes aligned with misfit dislocations. For (11 2 ¯ 2) and (20 2 ¯ 1) orientation, these dark stripes are perpendicular and parallel, respectively, to surface striation.